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VulnerabilityPublished Updated

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

Source GCVE Database

0
Authoritative record:CVE-2026-43374· High 7.8

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

Data as of 27 Oct 2026, 00:07 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
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–

Description

In the Linux kernel, the following vulnerability has been resolved: net: nexthop: fix percpu use-after-free in remove_nh_grp_entry When removing a nexthop from a group, remove_nh_grp_entry() publishes the new group via rcu_assign_pointer() then immediately frees the removed entry's percpu stats with free_percpu(). However, the synchronize_net() grace period in the caller remove_nexthop_from_groups() runs after the free. RCU readers that entered before the publish still see the old group and can dereference the freed stats via nh_grp_entry_stats_inc() -> get_cpu_ptr(nhge->stats), causing a use-after-free on percpu memory. Fix by deferring the free_percpu() until after synchronize_net() in the caller. Removed entries are chained via nh_list onto a local deferred free list. After the grace period completes and all RCU readers have finished, the percpu stats are safely freed.

References

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