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VulnerabilityPublished Updated

CVE-2026-43374: Linux kernel · net: nexthop: fix percpu use-after-free in remove_nh_grp_entry

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in b2662e7593e94ae09b1cf7ee5f09160a3612bcb2 : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:18 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in b2662e7593e94ae09b1cf7ee5f09160a3612bcb2, abf4feaee6405f1441929c6ebe7a250f2cd170a7, ab5ebab9664214ba41a7633cb4e72f128204f924 +1
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 8 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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.

What to do

Upgrade Linux kernel to b2662e7593e94ae09b1cf7ee5f09160a3612bcb2, abf4feaee6405f1441929c6ebe7a250f2cd170a7, ab5ebab9664214ba41a7633cb4e72f128204f924 or 9e08ad731862b22a87cc55f752e16d66cdc9e231.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ f4676ea74b8549cd88dbfe2a592ce4530039e61f, < b2662e7593e94ae09b1cf7ee5f09160a3612bcb2
Fixed in
  • b2662e7593e94ae09b1cf7ee5f09160a3612bcb2
LinuxLinuxAffected
  • ≥ f4676ea74b8549cd88dbfe2a592ce4530039e61f, < abf4feaee6405f1441929c6ebe7a250f2cd170a7
Fixed in
  • abf4feaee6405f1441929c6ebe7a250f2cd170a7
LinuxLinuxAffected
  • ≥ f4676ea74b8549cd88dbfe2a592ce4530039e61f, < ab5ebab9664214ba41a7633cb4e72f128204f924
Fixed in
  • ab5ebab9664214ba41a7633cb4e72f128204f924
LinuxLinuxAffected
  • ≥ f4676ea74b8549cd88dbfe2a592ce4530039e61f, < 9e08ad731862b22a87cc55f752e16d66cdc9e231
Fixed in
  • 9e08ad731862b22a87cc55f752e16d66cdc9e231
LinuxLinuxAffected
  • =6.9
Fixed in–

AI-suggested

A fix is available and has been applied in the Linux kernel. The fix defers freeing percpu stats until after the RCU grace period completes, preventing use-after-free. Users should update to a Linux kernel version that includes the fix identified by commits b2662b7593e94ae09b1cf7ee5f09160a3612bcb2, abf4feaee6405f1441929c6ebe7a250f2cd170a7, ab5ebab9664214ba41a7633cb4e72f128204f924, or 9e08ad731862b22a87cc55f752e16d66cdc9e231. No other mitigation is indicated by the vendor advisory.

Description

CVE-2026-43374 is a use-after-free vulnerability in the Linux kernel's nexthop component. It occurs when removing a nexthop from a group, where percpu stats are freed prematurely before the RCU grace period completes. This can lead to dereferencing freed memory, causing potential system instability or compromise. The issue has been fixed by deferring the freeing of percpu stats until after the RCU grace period. The vulnerability has a high severity with a CVSS score of 7.8.

References

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