CVE-2026-23455VulnerabilityPublished 6 Jul 2026Updated 30 Oct 2026

Red Hat Security Advisory: kernel security update

Affects Linux kernelSource GCVE Database

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Mentioned vulnerabilities

Authoritative record:CVE-2026-23455· Critical 9.1

Not known to be exploited · CVSS 9.1 Critical · fixed in Red Hat package updates : patch Linux kernel as a priority.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score

9.1Critical

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

EPSS: 1.5% chance of exploitation in 30 days – higher than 74% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in f173d0f4c0f689173f8cdac79991043a4a89bf66, f5e4f4e4cdb75ec36802059a94195a31f193da60, b652b05d51003ac074b912684f9ec7486231717b +5

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
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 Apr 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 29 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

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < f173d0f4c0f689173f8cdac79991043a4a89bf66	Fixed in f173d0f4c0f689173f8cdac79991043a4a89bf66
LinuxLinux	Affected ≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < f5e4f4e4cdb75ec36802059a94195a31f193da60	Fixed in f5e4f4e4cdb75ec36802059a94195a31f193da60
LinuxLinux	Affected ≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < b652b05d51003ac074b912684f9ec7486231717b	Fixed in b652b05d51003ac074b912684f9ec7486231717b
LinuxLinux	Affected ≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < 2121f5fbe88daff0f1fc5bc47d359426c74b86b0	Fixed in 2121f5fbe88daff0f1fc5bc47d359426c74b86b0
LinuxLinux	Affected ≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < 633e8f87dad32263f6a57dccdb873f042c062111	Fixed in 633e8f87dad32263f6a57dccdb873f042c062111
LinuxLinux	Affected ≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < 495e97af9e7249ee02b72bb1d0848a6efc3700f4	Fixed in 495e97af9e7249ee02b72bb1d0848a6efc3700f4

AI-suggested

Red Hat has released updated kernel packages that fix these vulnerabilities. Users of Red Hat Enterprise Linux 7 Extended Lifecycle Support should apply the kernel update as detailed in the Red Hat advisory (https://access.redhat.com/articles/11258) and reboot their systems to ensure the fixes take effect.

Description

Red Hat has issued a security advisory for kernel packages in Red Hat Enterprise Linux 7 Extended Lifecycle Support addressing multiple vulnerabilities. These include issues in netfilter's nf_conntrack_h323, dlm, ALSA aloop, and RDMA rxe subsystems. The vulnerabilities involve improper length checks, use-after-free, and double free conditions. The update requires a system reboot to take effect.

CWE-125Out-of-bounds Read (opens in a new tab)
Base weaknessCWE Top 25 (2025): #8
The product reads data past the end, or before the beginning, of the intended buffer.
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 · Language Selection
Use a language that provides appropriate memory abstractions.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Overread Buffers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-130Improper Handling of Length Parameter Inconsistency (opens in a new tab)
Base weakness
The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.
Implementation
When processing structured incoming data containing a size field followed by raw data, ensure that you identify and resolve any inconsistencies between the size field and the actual size of the data.
Implementation
Do not let the user control the size of the buffer.
Implementation
Validate that the length of the user-supplied data is consistent with the buffer size.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Buffer Overflow via Parameter Expansion (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-1341Multiple Releases of Same Resource or Handle (opens in a new tab)
Base weakness
The product attempts to close or release a resource or handle more than once, without any successful open between the close operations.
Implementation
Change the code's logic so that the resource is only closed once. This might require simplifying or refactoring. This fix can be simple to do in small code blocks, but more difficult when multiple closes are buried within complex conditionals.
Implementation · Refactoring
It can be effective to implement a flag that is (1) set when the resource is opened, (2) cleared when it is closed, and (3) checked before closing. This approach can be useful when there are disparate cases in which closes must be performed.
Implementation · Refactoring
When closing a resource, set the resource's associated variable to NULL or equivalent value for the given language. Some APIs will ignore this null value without causing errors.
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-364Signal Handler Race Condition (opens in a new tab)
Base weaknessLikelihood of exploit: Medium
The product uses a signal handler that introduces a race condition.
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Architecture and Design
Design signal handlers to only set flags, rather than perform complex functionality. These flags can then be checked and acted upon within the main program loop.
Implementation
Only use reentrant functions within signal handlers. Also, use validation to ensure that state is consistent while performing asynchronous actions that affect the state of execution.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V1.11.2 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 30 Oct 2026, 05:59 UTC

WeaknessesCWE-125, CWE-130, CWE-1341 +1

Technical details

References

Community reviews

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