CyberSecBulletin
CVE-2026-23242NVD status: Modified

Linux: NULL Pointer Dereference

Published Updated By the CyberSecBulletin desk

CVE-2026-23242 is a high-severity NULL pointer dereference vulnerability in Linux, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions ab61841633d10e56a58c1493a262f0d02dba2f5e, 8564dcc12fbb372d984ab45768cae9335777b274, ab957056192d6bd068b3759cb2077d859cca01f0 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.67% chance of exploitation within 30 days, higher than 53% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to ab61841633d10e56a58c1493a262f0d02dba2f5e or 8564dcc12fbb372d984ab45768cae9335777b274 or ab957056192d6bd068b3759cb2077d859cca01f0 or ffba40b67663567481fa8a1ed5d2da36897c175d, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.252 or 5.15.202 or 6.1.165 or 6.6.128, whichever matches your release line, or a later version.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux8b6a361b8c482f22ac99c3273285ff16b23fba91 up to, but not including, ab61841633d10e56a58c1493a262f0d02dba2f5e; 8b6a361b8c482f22ac99c3273285ff16b23fba91 up to, but not including, 8564dcc12fbb372d984ab45768cae9335777b274; 8b6a361b8c482f22ac99c3273285ff16b23fba91 up to, but not including, ab957056192d6bd068b3759cb2077d859cca01f0; 8b6a361b8c482f22ac99c3273285ff16b23fba91 up to, but not including, ffba40b67663567481fa8a1ed5d2da36897c175d; 8b6a361b8c482f22ac99c3273285ff16b23fba91 up to, but not including, 87b7a036d2c73d5bb3ae2d47dee23de465db3355; 8b6a361b8c482f22ac99c3273285ff16b23fba91 up to, but not including, 714c99e1dc8f85f446e05be02ba83972e981a817; 8b6a361b8c482f22ac99c3273285ff16b23fba91 up to, but not including, ce025f7f5d070596194315eb2e4e89d568b8a755; 8b6a361b8c482f22ac99c3273285ff16b23fba91 up to, but not including, 14ab3da122bd18920ad57428f6cf4fade8385142; and 1 more rangesab61841633d10e56a58c1493a262f0d02dba2f5e, 8564dcc12fbb372d984ab45768cae9335777b274, ab957056192d6bd068b3759cb2077d859cca01f0, ffba40b67663567481fa8a1ed5d2da36897c175d, 87b7a036d2c73d5bb3ae2d47dee23de465db3355, 714c99e1dc8f85f446e05be02ba83972e981a817
SiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0)V3.1.6 and later; V3.1.5 and later; V3.1.7 and laterNot stated
SiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0)V3.1.6 and later; V3.1.5 and later; V3.1.7 and laterNot stated
SiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0)V3.1.6 and later; V3.1.5 and later; V3.1.7 and laterNot stated
SiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0)V3.1.6 and later; V3.1.5 and later; V3.1.7 and laterNot stated
SiemensSIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0)V3.1.6 and later; V3.1.5 and later; V3.1.7 and laterNot stated
LinuxLinux Kernel5.3.1 up to, but not including, 5.10.252; 5.11 up to, but not including, 5.15.202; 5.16 up to, but not including, 6.1.165; 6.2 up to, but not including, 6.6.128; 6.7 up to, but not including, 6.12.75; 6.13 up to, but not including, 6.18.14; 6.19 up to, but not including, 6.19.4; 5.35.10.252, 5.15.202, 6.1.165, 6.6.128, 6.12.75, 6.18.14

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: Fix potential NULL pointer dereference in header processing If siw_get_hdr() returns -EINVAL before set_rx_fpdu_context(), qp->rx_fpdu can be NULL. The error path in siw_tcp_rx_data() dereferences qp->rx_fpdu->more_ddp_segs without checking, which may lead to a NULL pointer deref. Only check more_ddp_segs when rx_fpdu is present. KASAN splat: [ 101.384271] KASAN: null-ptr-deref in range [0x00000000000000c0-0x00000000000000c7] [ 101.385869] RIP: 0010:siw_tcp_rx_data+0x13ad/0x1e50

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: NULL Pointer Dereference

The product dereferences a pointer that it expects to be valid but is NULL.

How developers prevent this class of flaw

  • 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.
  • Select a programming language that is not susceptible to these issues.
  • Check the results of all functions that return a value and verify that the value is non-null before acting upon it.

More NULL Pointer Dereference vulnerabilities (CWE-476)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent NULL Pointer Dereference vulnerabilities

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