CVE-2026-31516

Local stale-memory access via XFRM teardown race

Published Apr 22, 2026 · Updated Apr 22, 2026

Use-after-free in the XFRM policy subsystem in Linux Kernel allows local users to access stale kernel memory during namespace teardown. xfrm_policy_fini() fails to synchronize policy_hthresh.work, so xfrm_hash_rebuild() can derive and dereference a freed struct net. A low-privileged local user must be able to send XFRM_MSG_NEWSPDINFO and trigger network-namespace teardown; no remote path is reported.

CVSS severity7.8
High
EPSS probability0.10%
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 access stale kernel memory during namespace teardown. xfrm_policy_fini() fails to synchronize policy_hthresh.work, so xfrm_hash_rebuild() can derive and dereference a freed struct net. A low-privileged local user must be able to send XFRM_MSG_NEWSPDINFO and trigger network-namespace teardown; no remote path is reported.

The record

CVE
CVE-2026-31516
Published
Apr 22, 2026
Updated
Apr 22, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-362
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 22, 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=3.18
  2. Affected versionversion=880a6fab8f6ba5b5abe59ea68533202ddea1012c <29fe3a61bcdce398ee3955101c39f89c01a8a77e
  3. Affected versionversion=880a6fab8f6ba5b5abe59ea68533202ddea1012c <4e2e77843fef473ef47e322d52436d8308582a96
  4. Affected versionversion=880a6fab8f6ba5b5abe59ea68533202ddea1012c <56ea2257b83ee29a543f158159e3d1abc1e3e4fe
  5. Affected versionversion=880a6fab8f6ba5b5abe59ea68533202ddea1012c <8854e9367465d784046362698731c1111e3b39b8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3.18; version=880a6fab8f6ba5b5abe59ea68533202ddea1012c <29fe3a61bcdce398ee3955101c39f89c01a8a77e; version=880a6fab8f6ba5b5abe59ea68533202ddea1012c <4e2e77843fef473ef47e322d52436d8308582a96; version=880a6fab8f6ba5b5abe59ea68533202ddea1012c <56ea2257b83ee29a543f158159e3d1abc1e3e4fe; version=880a6fab8f6ba5b5abe59ea68533202ddea1012c <8854e9367465d784046362698731c1111e3b39b8

Published CVSS scores

7.8Linux kernel CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.3UbuntuCVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
6.4Oracle LinuxCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
6.4Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

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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