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CVE-2026-43091

7.8 · 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 po…

Published May 6, 2026EPSS 0.18%

Overview

CVE-2026-43091 is a high-severity vulnerability. It was published on May 6, 2026 and has a CVSS 3.1 base score of 7.8 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical 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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refgit.kernel.org/stable/c/069daad4f2ae9c5c108131995529d5f02392c446Refgit.kernel.org/stable/c/33a3149dd81a1e2f52b80ee1e0fc380b39f3d028Refgit.kernel.org/stable/c/3733fce2871c9bca9dd18a1a23b1432ea215a094Refgit.kernel.org/stable/c/438b1f668ad58f46ce699bb48e4698a7839e3f9eRefgit.kernel.org/stable/c/b66920a3348c0f63ba18365248fa21fbf0b3a937

How CyberStrike helps

Frequently asked questions

What is CVE-2026-43091?

CVE-2026-43091 is a high-severity vulnerability. It was published on May 6, 2026 and has a CVSS 3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-43091?

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2026-43091?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-43091?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-43091 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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