CVE-2026-43091: Linux kernel · Use After Free
Source GCVE Database
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 6 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| 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
- nvd.nist.gov/vuln/detail/CVE-2026-43091 (opens in a new tab)
- git.kernel.org/stable/c/069daad4f2ae9c5c108131995529d5f02392c446 (opens in a new tab)
- git.kernel.org/stable/c/33a3149dd81a1e2f52b80ee1e0fc380b39f3d028 (opens in a new tab)
- git.kernel.org/stable/c/3733fce2871c9bca9dd18a1a23b1432ea215a094 (opens in a new tab)
- git.kernel.org/stable/c/438b1f668ad58f46ce699bb48e4698a7839e3f9e (opens in a new tab)
- git.kernel.org/stable/c/b66920a3348c0f63ba18365248fa21fbf0b3a937 (opens in a new tab)