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VulnerabilityPublished Updated

CVE-2026-43091: Linux kernel · Use After Free

Source GCVE Database

0
Authoritative record:CVE-2026-43091· High 7.8

Not known to be exploited · CVSS 7.8 High · fixed in b66920a3348c0f63ba18365248fa21fbf0b3a937 : 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 b66920a3348c0f63ba18365248fa21fbf0b3a937, 3733fce2871c9bca9dd18a1a23b1432ea215a094, 438b1f668ad58f46ce699bb48e4698a7839e3f9e +2
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 6 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 to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ e1e551bc56302b80ff930c966f9985095fb1b70d, < b66920a3348c0f63ba18365248fa21fbf0b3a937
Fixed in
  • b66920a3348c0f63ba18365248fa21fbf0b3a937
LinuxLinuxAffected
  • ≥ e1e551bc56302b80ff930c966f9985095fb1b70d, < 3733fce2871c9bca9dd18a1a23b1432ea215a094
Fixed in
  • 3733fce2871c9bca9dd18a1a23b1432ea215a094
LinuxLinuxAffected
  • ≥ e1e551bc56302b80ff930c966f9985095fb1b70d, < 438b1f668ad58f46ce699bb48e4698a7839e3f9e
Fixed in
  • 438b1f668ad58f46ce699bb48e4698a7839e3f9e
LinuxLinuxAffected
  • ≥ e1e551bc56302b80ff930c966f9985095fb1b70d, < 069daad4f2ae9c5c108131995529d5f02392c446
Fixed in
  • 069daad4f2ae9c5c108131995529d5f02392c446
LinuxLinuxAffected
  • ≥ e1e551bc56302b80ff930c966f9985095fb1b70d, < 33a3149dd81a1e2f52b80ee1e0fc380b39f3d028
Fixed in
  • 33a3149dd81a1e2f52b80ee1e0fc380b39f3d028
LinuxLinuxAffected
  • =4.9
Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: xfrm: Wait for RCU readers during policy netns exit xfrm_policy_fini() frees the policy_bydst hash tables after flushing the policy work items and deleting all policies, but it does not wait for concurrent RCU readers to leave their read-side critical sections first. The policy_bydst tables are published via rcu_assign_pointer() and are looked up through rcu_dereference_check(), so netns teardown must also wait for an RCU grace period before freeing the table memory. Fix this by adding synchronize_rcu() before freeing the policy hash tables.

References

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