CVE-2026-43091
xfrm: Wait for RCU readers during policy netns exit
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.
INFO
Published Date :
May 6, 2026, 10:16 a.m.
Last Modified :
May 8, 2026, 1:16 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Add synchronize_rcu() before freeing policy hash tables.
- Wait for RCU readers during policy netns exit.
References to Advisories, Solutions, and Tools
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CVE-2026-43091.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-43091 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
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stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-43091
weaknesses.
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CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 08, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 06, 2026
Action Type Old Value New Value Added 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. Added Reference https://git.kernel.org/stable/c/069daad4f2ae9c5c108131995529d5f02392c446 Added Reference https://git.kernel.org/stable/c/33a3149dd81a1e2f52b80ee1e0fc380b39f3d028 Added Reference https://git.kernel.org/stable/c/3733fce2871c9bca9dd18a1a23b1432ea215a094 Added Reference https://git.kernel.org/stable/c/438b1f668ad58f46ce699bb48e4698a7839e3f9e Added Reference https://git.kernel.org/stable/c/b66920a3348c0f63ba18365248fa21fbf0b3a937