CyberSecBulletin
CVE-2026-43248NVD status: Modified

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2026-43248 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 69ec8dd6696069c2f18430d0e05f81d604484ee8, 566899af053246406f2faf931044d2b0af8f34d2, ddb57354634b6ba851b79da45f1de42c646f27d0 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 0.16% 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 69ec8dd6696069c2f18430d0e05f81d604484ee8 or 566899af053246406f2faf931044d2b0af8f34d2 or ddb57354634b6ba851b79da45f1de42c646f27d0 or 7441d35d14d9a3d66d925d90cb73c75394e6d454, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.12.75 or 6.18.16 or 6.19.6, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxbda324fd037a6b0d44da5699574ce741ca161bc4 up to, but not including, 69ec8dd6696069c2f18430d0e05f81d604484ee8; bda324fd037a6b0d44da5699574ce741ca161bc4 up to, but not including, 566899af053246406f2faf931044d2b0af8f34d2; bda324fd037a6b0d44da5699574ce741ca161bc4 up to, but not including, ddb57354634b6ba851b79da45f1de42c646f27d0; bda324fd037a6b0d44da5699574ce741ca161bc4 up to, but not including, 7441d35d14d9a3d66d925d90cb73c75394e6d454; bda324fd037a6b0d44da5699574ce741ca161bc4 up to, but not including, 406db68f9cb976a8ddfafd631197264f2307e9c9; bda324fd037a6b0d44da5699574ce741ca161bc4 up to, but not including, cd025c1e876b4e262e71398236a1550486a73ede; 5.1969ec8dd6696069c2f18430d0e05f81d604484ee8, 566899af053246406f2faf931044d2b0af8f34d2, ddb57354634b6ba851b79da45f1de42c646f27d0, 7441d35d14d9a3d66d925d90cb73c75394e6d454, 406db68f9cb976a8ddfafd631197264f2307e9c9, cd025c1e876b4e262e71398236a1550486a73ede
LinuxLinux Kernel5.19 up to, but not including, 6.12.75; 6.13 up to, but not including, 6.18.16; 6.19 up to, but not including, 6.19.66.12.75, 6.18.16, 6.19.6

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 CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: vhost: move vdpa group bound check to vhost_vdpa Remove duplication by consolidating these here. This reduces the posibility of a parent driver missing them. While we're at it, fix a bug in vdpa_sim where a valid ASID can be assigned to a group equal to ngroups, causing an out of bound write.

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. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Write vulnerabilities

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