CVE-2026-43091

Kernel memory corruption via XFRM policy use-after-free

Published May 6, 2026 · Updated May 6, 2026

Use-after-free in the XFRM policy subsystem in Linux Kernel allows local users to corrupt kernel memory during network namespace teardown. xfrm_policy_fini() frees RCU-published policy_bydst hash tables without waiting for concurrent readers to finish, leaving stale pointers available during policy lookup. Exploitation requires CAP_NET_ADMIN in the target network namespace and a concurrent policy lookup; the result is kernel memory disclosure, corruption, or a crash.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the XFRM policy subsystem in Linux Kernel allows local users to corrupt kernel memory during network namespace teardown. xfrm_policy_fini() frees RCU-published policy_bydst hash tables without waiting for concurrent readers to finish, leaving stale pointers available during policy lookup. Exploitation requires CAP_NET_ADMIN in the target network namespace and a concurrent policy lookup; the result is kernel memory disclosure, corruption, or a crash.

The record

CVE
CVE-2026-43091
Published
May 6, 2026
Updated
May 6, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 6, 2026CVE publishedPublication date reported by the CVE source.
  2. May 6, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.9
  2. Affected versionversion=e1e551bc56302b80ff930c966f9985095fb1b70d <069daad4f2ae9c5c108131995529d5f02392c446
  3. Affected versionversion=e1e551bc56302b80ff930c966f9985095fb1b70d <33a3149dd81a1e2f52b80ee1e0fc380b39f3d028
  4. Affected versionversion=e1e551bc56302b80ff930c966f9985095fb1b70d <3733fce2871c9bca9dd18a1a23b1432ea215a094
  5. Affected versionversion=e1e551bc56302b80ff930c966f9985095fb1b70d <438b1f668ad58f46ce699bb48e4698a7839e3f9e
  6. Affected versionversion=e1e551bc56302b80ff930c966f9985095fb1b70d <b66920a3348c0f63ba18365248fa21fbf0b3a937

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=4.9; version=e1e551bc56302b80ff930c966f9985095fb1b70d <069daad4f2ae9c5c108131995529d5f02392c446; version=e1e551bc56302b80ff930c966f9985095fb1b70d <33a3149dd81a1e2f52b80ee1e0fc380b39f3d028; version=e1e551bc56302b80ff930c966f9985095fb1b70d <3733fce2871c9bca9dd18a1a23b1432ea215a094; version=e1e551bc56302b80ff930c966f9985095fb1b70d <438b1f668ad58f46ce699bb48e4698a7839e3f9e; version=e1e551bc56302b80ff930c966f9985095fb1b70d <b66920a3348c0f63ba18365248fa21fbf0b3a937

Published CVSS scores

7.8Linux kernel CVE teamCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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