CyberSecBulletin
CVE-2026-43208NVD status: Analyzed

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2026-43208 is a critical-severity out-of-bounds write vulnerability in Linux, with a CVSS 3.1 base score of 9.8 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 5455a232edea6b946b99449f15ca771a8874a5a6, ed712dc0d64dee5f0d05e4d8ca57711f8a9c850c, 8a8a9fac9efa6423fd74938b940cb7d731780718 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 0.48% chance of exploitation within 30 days, which is low compared with other CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update Linux to 5455a232edea6b946b99449f15ca771a8874a5a6 or ed712dc0d64dee5f0d05e4d8ca57711f8a9c850c or 8a8a9fac9efa6423fd74938b940cb7d731780718, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.18.16 or 6.19.6, 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
LinuxLinux48aa30443e52c9666d5cd5e67532e475f212337e up to, but not including, 5455a232edea6b946b99449f15ca771a8874a5a6; 48aa30443e52c9666d5cd5e67532e475f212337e up to, but not including, ed712dc0d64dee5f0d05e4d8ca57711f8a9c850c; 48aa30443e52c9666d5cd5e67532e475f212337e up to, but not including, 8a8a9fac9efa6423fd74938b940cb7d731780718; 6.185455a232edea6b946b99449f15ca771a8874a5a6, ed712dc0d64dee5f0d05e4d8ca57711f8a9c850c, 8a8a9fac9efa6423fd74938b940cb7d731780718
LinuxLinux Kernel6.18 up to, but not including, 6.18.16; 6.19 up to, but not including, 6.19.6; 7.06.18.16, 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
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
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:N/AC:L/PR:N/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: net: do not pass flow_id to set_rps_cpu() Blamed commit made the assumption that the RPS table for each receive queue would have the same size, and that it would not change. Compute flow_id in set_rps_cpu(), do not assume we can use the value computed by get_rps_cpu(). Otherwise we risk out-of-bound access and/or crashes.

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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