Red Hat Security Advisory: tomcat9 security update
Affects Red Hat tomcat9Source GCVE Database
Mentioned vulnerabilities
Not known to be exploited · CVSS 7.5 High.
Data as of 30 Oct 2026, 11:52 UTC
Thin evidence
One scorer or none| CISA-ADP | CVSS 3.1 | 7.5 |
|---|
- EPSS
- 4.6% chance of exploitation in 30 days – higher than 91% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Attack Vector
- Network
- Attack Complexity
- Low
- Privileges Required
- None
- User Interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Bold values are the worst case: easiest to exploit or largest impact.
- Attack Vector: Network
- The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
- Attack Complexity: Low
- Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
- Privileges Required: None
- The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
- User Interaction: None
- The vulnerable system can be exploited without any interaction from any user.
- Scope: Unchanged
- An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
- Confidentiality: None
- There is no loss of confidentiality within the impacted component.
- Integrity: None
- There is no loss of integrity within the impacted component.
- Availability: High
- There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).
Definitions: FIRST CVSS v3.1 specification.
Exploitation evidence
Disclosed: evidence found.
CVE published 3 Jul 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
- Disclosed
- The CVE record is public on cve.org. Its publication is t = 0.
- Detectable
- A public nuclei template can find exposed instances, for defenders and attackers alike.
- Weaponized
- A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
- Exploited in the wild
- CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
- Observed by OffSeq Mirage
- OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.
Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Mavenorg.apache.tomcat/tomcatpkg:maven/org.apache.tomcat/tomcatOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Red Hat has released updated tomcat9 packages for Red Hat Enterprise Linux 10.0 Extended Update Support that address these vulnerabilities. Users should apply the provided security update (tomcat9-9.0.120-1.el10_0 and related packages) as detailed in the Red Hat advisory RHSA-2026:67163 to remediate these issues. No additional mitigation steps are indicated beyond applying the official update.
Description
A security update for Apache Tomcat 9 addresses multiple vulnerabilities including improper input validation, authentication bypasses, HTTP/2 header validation issues, information disclosure during WebSocket authentication, improper authorization, case sensitivity handling flaws, security constraint bypasses, and insufficient documentation leading to insecure configurations. These issues affect Red Hat Enterprise Linux 10.0 Extended Update Support versions of tomcat9 and related components.
Impact
The vulnerabilities collectively allow attackers to bypass authentication and authorization controls, cause improper input validation, expose sensitive HTTP authentication headers during WebSocket authentication, and bypass security constraints. These issues could lead to unauthorized access, information disclosure, and potential security bypasses in affected Tomcat 9 deployments on Red Hat Enterprise Linux 10.0 Extended Update Support.
- CWE-835Loop with Unreachable Exit Condition (Infinite Loop) (opens in a new tab)
Base weakness
The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.
- CWE-400Uncontrolled Resource Consumption (opens in a new tab)
Class weaknessLikelihood of exploit: High
The product does not properly control the allocation and maintenance of a limited resource.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place.
Architecture and Design
Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or; uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed.
Architecture and Design
Ensure that protocols have specific limits of scale placed on them.
- OWASP Cheat Sheets
- OWASP ASVS 4.0.3
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-178Improper Handling of Case Sensitivity (opens in a new tab)
Base weakness
The product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.
Architecture and Design · Input Validation
Avoid making decisions based on names of resources (e.g. files) if those resources can have alternate names.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-384Session Fixation (opens in a new tab)
Compound weaknessOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions.
Architecture and Design
Invalidate any existing session identifiers prior to authorizing a new user session.
Architecture and Design
For platforms such as ASP that do not generate new values for sessionid cookies, utilize a secondary cookie. In this approach, set a secondary cookie on the user's browser to a random value and set a session variable to the same value.
Operation · Firewall
Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
- OWASP ASVS 4.0.3
- Attack patterns
- Session Credential Falsification through Forging (opens in a new tab)
- Accessing/Intercepting/Modifying HTTP Cookies (opens in a new tab)
- Manipulating Opaque Client-based Data Tokens (opens in a new tab)
- Session Credential Falsification through Prediction (opens in a new tab)
- Reusing Session IDs (aka Session Replay) (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-150Improper Neutralization of Escape, Meta, or Control Sequences (opens in a new tab)
Variant weakness
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as escape, meta, or control character sequences when they are sent to a downstream component.
Developers should anticipate that escape, meta and control characters/sequences will be injected/removed/manipulated in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only valid, expected and appropriate input is processed by the system.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Implementation · Output Encoding
While it is risky to use dynamically-generated query strings, code, or commands that mix control and data together, sometimes it may be unavoidable. Properly quote arguments and escape any special characters within those arguments.
- OWASP Cheat Sheets
- OWASP ASVS 4.0.3
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-404Improper Resource Shutdown or Release (opens in a new tab)
Class weaknessLikelihood of exploit: Medium
The product does not release or incorrectly releases a resource before it is made available for re-use.
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Implementation
It is good practice to be responsible for freeing all resources you allocate and to be consistent with how and where you free memory in a function. If you allocate memory that you intend to free upon completion of the function, you must be sure to free the memory at all exit points for that function including error…
Implementation
Memory should be allocated/freed using matching functions such as malloc/free, new/delete, and new[]/delete[].
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-1289Improper Validation of Unsafe Equivalence in Input (opens in a new tab)
Base weakness
The product receives an input value that is used as a resource identifier or other type of reference, but it does not validate or incorrectly validates that the input is equivalent to a potentially-unsafe value.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
- OWASP Cheat Sheets
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-20Improper Input Validation (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #18OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Attack Surface Reduction
Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build "recognizers" for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of…
Architecture and Design · Libraries or Frameworks
Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any…
- OWASP Cheat Sheets
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-444Inconsistent Interpretation of HTTP Requests (HTTP Request Smuggling) (opens in a new tab)
Base weaknessOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.
Implementation
Use a web server that employs a strict HTTP parsing procedure, such as Apache.
Implementation
Use only SSL communication.
Implementation
Terminate the client session after each request.
- OWASP Cheat Sheets
- OWASP ASVS 4.0.3
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-601URL Redirection to Untrusted Site (Open Redirect) (opens in a new tab)
Base weaknessLikelihood of exploit: LowOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Architecture and Design
Use an intermediate disclaimer page that provides the user with a clear warning that they are leaving the current site. Implement a long timeout before the redirect occurs, or force the user to click on the link. Be careful to avoid XSS problems (CWE-79) when generating the disclaimer page.
Architecture and Design · Enforcement by Conversion
When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.
- OWASP Cheat Sheets
- OWASP ASVS 4.0.3
- Attack patterns
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-303Incorrect Implementation of Authentication Algorithm (opens in a new tab)
Base weaknessOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The requirements for the product dictate the use of an established authentication algorithm, but the implementation of the algorithm is incorrect.
- OWASP Cheat Sheets
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-184Incomplete List of Disallowed Inputs (opens in a new tab)
Base weaknessOWASP Top 10 A03:2021: Injection (opens in a new tab)
The product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are not allowed by policy or otherwise require other action to neutralize before additional processing takes place, but the list is incomplete.
Implementation · Input Validation
Do not rely exclusively on detecting disallowed inputs. There are too many variants to encode a character, especially when different environments are used, so there is a high likelihood of missing some variants. Only use detection of disallowed inputs as a mechanism for detecting suspicious activity.
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-838Inappropriate Encoding for Output Context (opens in a new tab)
Base weakness
The product uses or specifies an encoding when generating output to a downstream component, but the specified encoding is not the same as the encoding that is expected by the downstream component.
Implementation · Output Encoding
Use context-aware encoding. That is, understand which encoding is being used by the downstream component, and ensure that this encoding is used. If an encoding can be specified, do so, instead of assuming that the default encoding is the same as the default being assumed by the downstream component.
Architecture and Design · Output Encoding
Where possible, use communications protocols or data formats that provide strict boundaries between control and data. If this is not feasible, ensure that the protocols or formats allow the communicating components to explicitly state which encoding/decoding method is being used.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- OWASP Cheat Sheets
- OWASP ASVS 4.0.3
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-538Insertion of Sensitive Information into Externally-Accessible File or Directory (opens in a new tab)
Base weaknessOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product places sensitive information into files or directories that are accessible to actors who are allowed to have access to the files, but not to the sensitive information.
Architecture and Design · Operation · System Configuration
Do not expose file and directory information to the user.
- OWASP Cheat Sheets
- Attack patterns
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-770Allocation of Resources Without Limits or Throttling (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #25
The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
Requirements
Clearly specify the minimum and maximum expectations for capabilities, and dictate which behaviors are acceptable when resource allocation reaches limits.
Architecture and Design
Limit the amount of resources that are accessible to unprivileged users. Set per-user limits for resources. Allow the system administrator to define these limits. Be careful to avoid CWE-410.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended.
- OWASP Cheat Sheets
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-1286Improper Validation of Syntactic Correctness of Input (opens in a new tab)
Base weakness
The product receives input that is expected to be well-formed - i.e., to comply with a certain syntax - but it does not validate or incorrectly validates that the input complies with the syntax.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
- OWASP Cheat Sheets
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-201Insertion of Sensitive Information Into Sent Data (opens in a new tab)
Base weaknessOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor.
Requirements
Specify which data in the software should be regarded as sensitive. Consider which types of users should have access to which types of data.
Implementation
Ensure that any possibly sensitive data specified in the requirements is verified with designers to ensure that it is either a calculated risk or mitigated elsewhere.
System Configuration
Setup default error messages so that unexpected errors do not disclose sensitive information.
- OWASP Cheat Sheets
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-208Observable Timing Discrepancy (opens in a new tab)
Base weakness
Two separate operations in a product require different amounts of time to complete, in a way that is observable to an actor and reveals security-relevant information about the state of the product, such as whether a particular operation was successful or not.
- OWASP Cheat Sheets
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-551Incorrect Behavior Order: Authorization Before Parsing and Canonicalization (opens in a new tab)
Base weakness
If a web server does not fully parse requested URLs before it examines them for authorization, it may be possible for an attacker to bypass authorization protection.
Architecture and Design
URL Inputs should be decoded and canonicalized to the application's current internal representation before being validated and processed for authorization. Make sure that your application does not decode the same input twice.
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-79Improper Neutralization of Input During Web Page Generation (Cross-site Scripting) (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #1OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Implementation · Architecture and Design
Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages.
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide…
- OWASP Cheat Sheets
- OWASP ASVS 4.0.3
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-358Name not in the CWE catalogue (opens in a new tab)
- CWE-390Name not in the CWE catalogue (opens in a new tab)
- CWE-778Name not in the CWE catalogue (opens in a new tab)
- CWE-294Name not in the CWE catalogue (opens in a new tab)
- CWE-305Name not in the CWE catalogue (opens in a new tab)
- CWE-807Name not in the CWE catalogue (opens in a new tab)
- CWE-1188Name not in the CWE catalogue (opens in a new tab)
- GCVE source
- db.gcve.eu
- Csaf Category
- csaf_security_advisory
- Csaf Version
- 2.0
- Publisher
- Red Hat Product Security
- Advisory ID
- RHSA-2026:67163
- Vendor Severity
- high
- CVE Count
- 30
- Additional Cves
- CVE-2024-38286, CVE-2025-46701, CVE-2025-55668, CVE-2025-55754, CVE-2025-61795, CVE-2025-66614, CVE-2026-24733, CVE-2026-24880, CVE-2026-25854, CVE-2026-29145, CVE-2026-32990, CVE-2026-34483, CVE-2026-34487, CVE-2026-41284, CVE-2026-41293, CVE-2026-42498, CVE-2026-43512, CVE-2026-43513, CVE-2026-43514, CVE-2026-43515, CVE-2026-50229, CVE-2026-53404, CVE-2026-53434, CVE-2026-55276, CVE-2026-55955, CVE-2026-55956, CVE-2026-55957, CVE-2026-59083, CVE-2026-59084
References
- access.redhat.com/errata/RHSA-2026:67163 (opens in a new tab)
- access.redhat.com/security/updates/classification/ (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2457025 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2476511 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2476513 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2476516 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2476519 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2476520 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2494669 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2499917 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2499931 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_67163.json (opens in a new tab)
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