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CVE-2026-23326NVD status: Analyzed

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2026-23326 is a high-severity out-of-bounds write vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 5172adf9efb8298a52f4dcdc3f98d4d9d1e06a6d, 2a9ea988465ece5b6896b1bdc144170a64e84c35, 645c6d8376ad4913cbffe0e0c2cca0c4febbe596 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 0.14% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 5172adf9efb8298a52f4dcdc3f98d4d9d1e06a6d or 2a9ea988465ece5b6896b1bdc144170a64e84c35 or 645c6d8376ad4913cbffe0e0c2cca0c4febbe596 or b38cbd4af5034635cff109e08788c63f956f3a69, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.18.17 or 6.19.7, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux560c974b7ccd95bb9ff20df77f6654283e45c9c6 up to, but not including, 5172adf9efb8298a52f4dcdc3f98d4d9d1e06a6d; fd5614763805d6f386bd07cc53558f88b1b1eb62 up to, but not including, 2a9ea988465ece5b6896b1bdc144170a64e84c35; b692bf9a7543af7ad11a59d182a3757578f0ba53 up to, but not including, 645c6d8376ad4913cbffe0e0c2cca0c4febbe596; b692bf9a7543af7ad11a59d182a3757578f0ba53 up to, but not including, b38cbd4af5034635cff109e08788c63f956f3a69; b692bf9a7543af7ad11a59d182a3757578f0ba53 up to, but not including, 60abb0ac11dccd6b98fd9182bc5f85b621688861; 6.135172adf9efb8298a52f4dcdc3f98d4d9d1e06a6d, 2a9ea988465ece5b6896b1bdc144170a64e84c35, 645c6d8376ad4913cbffe0e0c2cca0c4febbe596, b38cbd4af5034635cff109e08788c63f956f3a69, 60abb0ac11dccd6b98fd9182bc5f85b621688861
LinuxLinux Kernel6.13.1 up to, but not including, 6.18.17; 6.19 up to, but not including, 6.19.7; 6.13; 7.06.18.17, 6.19.7

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
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

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

Official description

In the Linux kernel, the following vulnerability has been resolved: xsk: Fix fragment node deletion to prevent buffer leak After commit b692bf9a7543 ("xsk: Get rid of xdp_buff_xsk::xskb_list_node"), the list_node field is reused for both the xskb pool list and the buffer free list, this causes a buffer leak as described below. xp_free() checks if a buffer is already on the free list using list_empty(&xskb->list_node). When list_del() is used to remove a node from the xskb pool list, it doesn't reinitialize the node pointers. This means list_empty() will return false even after the node has been removed, causing xp_free() to incorrectly skip adding the buffer to the free list. Fix this by using list_del_init() instead of list_del() in all fragment handling paths, this ensures the list node is reinitialized after removal, allowing the list_empty() to work correctly.

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

The underlying weakness: Out-of-bounds Write

The product writes data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Out-of-bounds Write vulnerabilities (CWE-787)

Timeline

  1. CVE record published.
  2. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Write vulnerabilities

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