VulnerabilityPublished 23 Sep 2026

CVE-2026-79677: Apache Tomcat · Missing release of resource after effective lifetime

Affects Apache TomcatSource CVE Database V5

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Not known to be exploited · CVSS 7.5 High.

Data as of 6 Nov 2026, 23:24 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 36% 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 23 Sep 2026
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 7 Nov 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
Apache Software FoundationApache Tomcat	Affected >=11.0.0-M1 <=11.0.25 >=10.1.0-M1 <=10.1.59 >=9.0.0.M1 <=9.0.121 >=8.5.0 <=8.5.100 >=7.0.43 <=7.0.109	Fixed in–
Mavenorg.apache.tomcat/tomcat`pkg:maven/org.apache.tomcat/tomcat`Other threats	Affected >=11.0.0-M1 <=11.0.25 >=10.1.0-M1 <=10.1.59 >=9.0.0.M1 <=9.0.121 >=8.5.0 <=8.5.100 >=7.0.43 <=7.0.109	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Users should upgrade affected Apache Tomcat versions to 11.0.26, 10.1.60, or 9.0.122 or later, where the issue is fixed. No other mitigation or workaround is indicated by the vendor advisory. Patch status is confirmed as fixed in these versions.

Description

CVE-2026-79677 is a high-severity vulnerability in Apache Tomcat involving a missing release of resources after their effective lifetime, specifically related to asynchronous WebSocket writes. This flaw can cause denial of service due to lost timeouts. It affects multiple versions across several major Tomcat branches, including 7.0.43 through 7.0.109, 8.5.0 through 8.5.100, 9.0.0.M1 through 9.0.121, 10.1.0-M1 through 10.1.59, and 11.0.0-M1 through 11.0.25. Fixed versions are 11.0.26, 10.1.60, and 9.0.122.

CWE-772Missing Release of Resource after Effective Lifetime (opens in a new tab)
Base weaknessLikelihood of exploit: High
The product does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed.
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 resources in a function. If you allocate resources that you intend to free upon completion of the function, you must be sure to free the resources at all exit points for that function including…
Operation · Architecture and Design · Resource Limitation
Use resource-limiting settings provided by the operating system or environment. For example, when managing system resources in POSIX, setrlimit() can be used to set limits for certain types of resources, and getrlimit() can determine how many resources are available.
Attack patterns
HTTP DoS (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-1025Comparison Using Wrong Factors (opens in a new tab)
Class weakness
The code performs a comparison between two entities, but the comparison examines the wrong factors or characteristics of the entities.

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 17 Oct 2026, 23:37 UTC

WeaknessesCWE-772, CWE-1025

Technical details

References

Community reviews

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