CVE-2025-40256Public exploit

Kernel resource leak via orphaned IPComp tunnels

Published Dec 4, 2025 · Updated May 11, 2026

Resource leakage in the Linux kernel 6.16 through 6.17.9 allows local users to consume kernel resources through failed IPComp state creation. xfrm_state_gc_destroy omits xfrm_state_delete_tunnel when a fully initialized state fails before list insertion, leaving its fallback tunnel linked. Reaching the affected add, update, or migration paths requires local low-privileged access, and the documented consequence is an orphaned fallback tunnel rather than code execution.

CVSS severity7.1
High
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource leakage in the Linux kernel 6.16 through 6.17.9 allows local users to consume kernel resources through failed IPComp state creation. xfrm_state_gc_destroy omits xfrm_state_delete_tunnel when a fully initialized state fails before list insertion, leaving its fallback tunnel linked. Reaching the affected add, update, or migration paths requires local low-privileged access, and the documented consequence is an orphaned fallback tunnel rather than code execution.

The record

CVE
CVE-2025-40256
Published
Dec 4, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 4, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=0da961fa46da1b37ef868d9b603bd202136f8f8e <64441724387b4ac92f67ef51caaaeffe99c950d1
  2. Affected versionversion=1b28a7fae0128fa140a7dccd995182ff6cd1c67b <57b72d74d4651dc19d046308a8304eb9abfe66ac
  3. Affected versionversion=4b2c17d0f9be8b58bb30468bc81a4b61c985b04e <1dad653643f28ccc89be93f9440b8804cded85b2
  4. Affected versionversion=6.16
  5. Affected versionversion=b441cf3f8c4b8576639d20c8eb4aa32917602ecd <10deb69864840ccf96b00ac2ab3a2055c0c04721
  6. Affected versionversion=b441cf3f8c4b8576639d20c8eb4aa32917602ecd <d6fe5c740c573af10943b8353992e1325cdb2715
  7. Affected versionversion=d0e0d1097118461463b76562c7ebaabaa5b90b13 <763e5c351206c1e4d910db4a1159053f6263689c
  8. Affected versionversion=dc3636912d41770466543623cb76e7b88fdb42c7 <f7d879c19d306512c2e260f37e8a3e5c85e37c50

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0da961fa46da1b37ef868d9b603bd202136f8f8e <64441724387b4ac92f67ef51caaaeffe99c950d1; version=1b28a7fae0128fa140a7dccd995182ff6cd1c67b <57b72d74d4651dc19d046308a8304eb9abfe66ac; version=4b2c17d0f9be8b58bb30468bc81a4b61c985b04e <1dad653643f28ccc89be93f9440b8804cded85b2; version=6.16; version=b441cf3f8c4b8576639d20c8eb4aa32917602ecd <10deb69864840ccf96b00ac2ab3a2055c0c04721; version=b441cf3f8c4b8576639d20c8eb4aa32917602ecd <d6fe5c740c573af10943b8353992e1325cdb2715; version=d0e0d1097118461463b76562c7ebaabaa5b90b13 <763e5c351206c1e4d910db4a1159053f6263689c; version=dc3636912d41770466543623cb76e7b88fdb42c7 <f7d879c19d306512c2e260f37e8a3e5c85e37c50

Published CVSS scores

7.1Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/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 exploitPublished

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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