What is CVE-2026-43091?

CVE-2026-43091 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10, affecting Linux kernel versions from 4.9 onward and patched in 6.6.136, 6.12.83, 6.18.24 and others. CVE-2026-43091 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-43091?

CVE-2026-43091 has a CVSS score of 7.8 out of 10, rated High severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2026-43091?

Yes, CVE-2026-43091 has been patched. Fixed versions include 6.6.136, 6.12.83, 6.18.24 and others. If you are running Linux kernel 4.9 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-43091 actively exploited?

CVE-2026-43091 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-43091

High

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.

Package Linux Kernel

Published 2026-05-06

Last modified 2026-05-19

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

7.8

out of 10

High

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected versions

Linux kernel versions 4.9 and later are affected. Fixed in 6.6.136, 6.12.83, 6.18.24, 6.19.14, 7.0 and their respective stable series.

Affected from

≥ 4.9

Fixed in

✓ 6.6.136 6.6.x ✓ 6.12.83 6.12.x ✓ 6.18.24 6.18.x ✓ 6.19.14 6.19.x ✓ 7.0

References

The following references provide additional information about CVE-2026-43091 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Kernel patch commit
https://git.kernel.org/stable/c/069daad4f2ae9c5c108131995529d5f02392c446
Patch
Kernel patch commit
https://git.kernel.org/stable/c/33a3149dd81a1e2f52b80ee1e0fc380b39f3d028
Patch
Kernel patch commit
https://git.kernel.org/stable/c/3733fce2871c9bca9dd18a1a23b1432ea215a094
Patch

5 patch commits total View all on NVD

Details

CVE ID CVE-2026-43091

Severity High

CVSS score 7.8 / 10

CVSS version 3.1

Published 2026-05-06

Modified 2026-05-19

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-43091?

CVE-2026-43091 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 . It affects Linux kernel versions from 4.9 onward and has been patched in 6.6.136, 6.12.83, 6.18.24 and others. CVE-2026-43091 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-43091?

CVE-2026-43091 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Is there a patch available for CVE-2026-43091?

Yes — CVE-2026-43091 has been patched. Fixed versions include 6.6.136, 6.12.83, 6.18.24 and others. If you are running Linux kernel 4.9 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-43091 actively exploited?

No — CVE-2026-43091 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.