CVE-2026-43091

Summary

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxe1e551bc56302b80ff930c966f9985095fb1b70d < b66920a3348c0f63ba18365248fa21fbf0b3a937affected
LinuxLinuxe1e551bc56302b80ff930c966f9985095fb1b70d < 438b1f668ad58f46ce699bb48e4698a7839e3f9eaffected
LinuxLinuxe1e551bc56302b80ff930c966f9985095fb1b70d < 3733fce2871c9bca9dd18a1a23b1432ea215a094affected
LinuxLinuxe1e551bc56302b80ff930c966f9985095fb1b70d < 33a3149dd81a1e2f52b80ee1e0fc380b39f3d028affected
LinuxLinuxe1e551bc56302b80ff930c966f9985095fb1b70d < 069daad4f2ae9c5c108131995529d5f02392c446affected
LinuxLinux4.9affected
LinuxLinux0 < 4.9unaffected
LinuxLinux6.6.136 <= 6.6.*unaffected
LinuxLinux6.12.83 <= 6.12.*unaffected
LinuxLinux6.18.24 <= 6.18.*unaffected
LinuxLinux6.19.14 <= 6.19.*unaffected
LinuxLinux7.0 <= *unaffected

Weaknesses

References