How severe is CVE-2026-43091?

CVE-2026-43091 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-43091 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-43091?

CVE-2026-43091 primarily affects Linux Linux Kernel. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-43091?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-43091 have an EU (EUVD) identifier?

Yes. CVE-2026-43091 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27592.

When was CVE-2026-43091 published?

CVE-2026-43091 was published on 2026-05-06 and last updated on 2026-06-17.

CVE-2026-43091

CVE-2026-43091 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.8)
EPSS exploit prediction: 0% (3rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-27592
Affected product: Linux Linux Kernel
Published: 2026-05-06
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-43091?: 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.
How severe is CVE-2026-43091?: CVE-2026-43091 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-43091 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-43091?: CVE-2026-43091 primarily affects Linux Linux Kernel. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-43091?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-43091 have an EU (EUVD) identifier?: Yes. CVE-2026-43091 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27592.
When was CVE-2026-43091 published?: CVE-2026-43091 was published on 2026-05-06 and last updated on 2026-06-17.

References

Affected products (8)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*

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