VulnerabilityPublished 18 Mar 2026Updated 19 Oct 2026

CVE-2026-23242: Linux kernel · NULL Pointer Dereference

Affects Linux kernelSource CVE Database V5

Not known to be exploited · CVSS 7.5 High · fixed in ffba40b67663567481fa8a1ed5d2da36897c175d : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:35 UTC

CVSS 3.1 base score

7.5High

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

EPSS

0.6% chance of exploitation in 30 days – higher than 49% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers can reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-16.

Patch

Available – fixed in ffba40b67663567481fa8a1ed5d2da36897c175d, ce025f7f5d070596194315eb2e4e89d568b8a755, ab957056192d6bd068b3759cb2077d859cca01f0 +5

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 18 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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 ≥ 8b6a361b8c482f22ac99c3273285ff16b23fba91, < ffba40b67663567481fa8a1ed5d2da36897c175d	Fixed in ffba40b67663567481fa8a1ed5d2da36897c175d
LinuxLinux	Affected ≥ 8b6a361b8c482f22ac99c3273285ff16b23fba91, < ce025f7f5d070596194315eb2e4e89d568b8a755	Fixed in ce025f7f5d070596194315eb2e4e89d568b8a755
LinuxLinux	Affected ≥ 8b6a361b8c482f22ac99c3273285ff16b23fba91, < ab957056192d6bd068b3759cb2077d859cca01f0	Fixed in ab957056192d6bd068b3759cb2077d859cca01f0
LinuxLinux	Affected ≥ 8b6a361b8c482f22ac99c3273285ff16b23fba91, < ab61841633d10e56a58c1493a262f0d02dba2f5e	Fixed in ab61841633d10e56a58c1493a262f0d02dba2f5e
LinuxLinux	Affected ≥ 8b6a361b8c482f22ac99c3273285ff16b23fba91, < 8564dcc12fbb372d984ab45768cae9335777b274	Fixed in 8564dcc12fbb372d984ab45768cae9335777b274
LinuxLinux	Affected ≥ 8b6a361b8c482f22ac99c3273285ff16b23fba91, < 714c99e1dc8f85f446e05be02ba83972e981a817	Fixed in 714c99e1dc8f85f446e05be02ba83972e981a817

AI-suggested

This vulnerability has been fixed in multiple Linux kernel commits as listed in the established facts. Users and administrators should update their Linux kernel to a version that includes these fixes to mitigate the issue. Since this is not a cloud service, manual patching is required. No additional mitigation steps are indicated by the vendor advisory.

Description

A high-severity vulnerability (CVE-2026-23242) in the Linux kernel's RDMA/siw subsystem involves a potential NULL pointer dereference during header processing. The issue occurs if siw_get_hdr() returns -EINVAL before set_rx_fpdu_context(), leaving qp->rx_fpdu as NULL. The error path in siw_tcp_rx_data() then dereferences qp->rx_fpdu->more_ddp_segs without verifying qp->rx_fpdu is non-NULL, causing a NULL pointer dereference and potential kernel crash.

Impact

Exploitation of this vulnerability can cause a denial of service by triggering a kernel NULL pointer dereference, resulting in a system crash. There is no indication of confidentiality or integrity impact. The vulnerability can be triggered remotely over the network without privileges or user interaction.

Summary

CVE-2026-23242 addresses a NULL pointer dereference vulnerability in the Linux kernel's RDMA/siw code. Specifically, if siw_get_hdr() returns -EINVAL before set_rx_fpdu_context() is called, qp->rx_fpdu remains NULL. The function siw_tcp_rx_data() erroneously dereferences qp->rx_fpdu->more_ddp_segs without checking if qp->rx_fpdu is valid, leading to a NULL pointer dereference and kernel crash. The vulnerability is identified by KASAN reports and is fixed in multiple Linux kernel commits. The CVSS 3.1 score is 7.5 (high), indicating network attack vector, low complexity, no privileges or user interaction required, and impact limited to availability (kernel crash).

CWE-476NULL Pointer Dereference (opens in a new tab)
Base weaknessLikelihood of exploit: MediumCWE Top 25 (2025): #13OWASP Top 10 A10:2025: Mishandling of Exceptional Conditions (opens in a new tab)
The product dereferences a pointer that it expects to be valid but is NULL.
Implementation
For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
Requirements
Select a programming language that is not susceptible to these issues.
Implementation
Check the results of all functions that return a value and verify that the value is non-null before acting upon it.
OWASP Cheat Sheets
Logging (opens in a new tab)
Error Handling (opens in a new tab)
OWASP ASVS 4.0.3
V11.1.7 (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 26 Oct 2026, 13:35 UTC

WeaknessesCWE-476

Technical details

References

Community reviews

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