CVE-2025-40215

Local kernel compromise via delayed fallback-state deletion

Published Dec 4, 2025 · Updated Aug 5, 2026

Use-after-free in the Linux kernel XFRM subsystem 2.6.29 through 6.15 allows local users to corrupt kernel memory via IPComp. xfrm_state_fini can free namespace hash tables while an IP reassembly queue still holds a secpath reference, then later unlink the delayed fallback state through freed list and hash storage. Triggering requires a user namespace with CAP_NET_ADMIN, a configured IPComp tunnel-mode state, crafted fragmented traffic, and namespace teardown; consequences include kernel-memory disclosure, control-flow hijack, or a kernel panic.

CVSS severity7.8
High
EPSS probability0.14%
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 Linux kernel XFRM subsystem 2.6.29 through 6.15 allows local users to corrupt kernel memory via IPComp. xfrm_state_fini can free namespace hash tables while an IP reassembly queue still holds a secpath reference, then later unlink the delayed fallback state through freed list and hash storage. Triggering requires a user namespace with CAP_NET_ADMIN, a configured IPComp tunnel-mode state, crafted fragmented traffic, and namespace teardown; consequences include kernel-memory disclosure, control-flow hijack, or a kernel panic.

The record

CVE
CVE-2025-40215
Published
Dec 4, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 4, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=2.6.29
  2. Affected versionversion=9d4139c76905833afcb77fe8ccc17f302a0eb9ab <0da961fa46da1b37ef868d9b603bd202136f8f8e
  3. Affected versionversion=9d4139c76905833afcb77fe8ccc17f302a0eb9ab <1b28a7fae0128fa140a7dccd995182ff6cd1c67b
  4. Affected versionversion=9d4139c76905833afcb77fe8ccc17f302a0eb9ab <4b2c17d0f9be8b58bb30468bc81a4b61c985b04e
  5. Affected versionversion=9d4139c76905833afcb77fe8ccc17f302a0eb9ab <b441cf3f8c4b8576639d20c8eb4aa32917602ecd
  6. Affected versionversion=9d4139c76905833afcb77fe8ccc17f302a0eb9ab <d0e0d1097118461463b76562c7ebaabaa5b90b13
  7. Affected versionversion=9d4139c76905833afcb77fe8ccc17f302a0eb9ab <dc3636912d41770466543623cb76e7b88fdb42c7

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.29; version=9d4139c76905833afcb77fe8ccc17f302a0eb9ab <0da961fa46da1b37ef868d9b603bd202136f8f8e; version=9d4139c76905833afcb77fe8ccc17f302a0eb9ab <1b28a7fae0128fa140a7dccd995182ff6cd1c67b; version=9d4139c76905833afcb77fe8ccc17f302a0eb9ab <4b2c17d0f9be8b58bb30468bc81a4b61c985b04e; version=9d4139c76905833afcb77fe8ccc17f302a0eb9ab <b441cf3f8c4b8576639d20c8eb4aa32917602ecd; version=9d4139c76905833afcb77fe8ccc17f302a0eb9ab <d0e0d1097118461463b76562c7ebaabaa5b90b13; version=9d4139c76905833afcb77fe8ccc17f302a0eb9ab <dc3636912d41770466543623cb76e7b88fdb42c7

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

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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