CVE-2025-40257

Kernel crash via MPTCP address-timer race

Published Dec 4, 2025 · Updated Aug 5, 2026

Use-after-free in the MPTCP path manager in Linux 5.10 and later and SINEC OS before V4.0 allows local users to crash the kernel. mptcp_pm_del_add_timer() can call sk_stop_timer_sync() on an address entry that another worker has already freed because the timer path lacks RCU protection. The race requires local low-privileged access and MPTCP activity; the published impact is a kernel crash without confidentiality or integrity loss.

CVSS severity5.5
Medium
EPSS probability0.46%
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 MPTCP path manager in Linux 5.10 and later and SINEC OS before V4.0 allows local users to crash the kernel. mptcp_pm_del_add_timer() can call sk_stop_timer_sync() on an address entry that another worker has already freed because the timer path lacks RCU protection. The race requires local low-privileged access and MPTCP activity; the published impact is a kernel crash without confidentiality or integrity loss.

The record

CVE
CVE-2025-40257
Published
Dec 4, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-20, T1499.004
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=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <385ddc0f008f24d1e7d03be998b3a98a37bd29ff
  2. Affected versionversion=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <426358d9be7ce3518966422f87b96f1bad27295f
  3. Affected versionversion=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <6d3275d4ca62e2c02e1b7e8cd32db59df91c14b7
  4. Affected versionversion=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <9be29f8e7ce4e147e56caac2c3a0ce3573cf9c17
  5. Affected versionversion=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <bbbd75346c8e6490b19c2ba90f38ea66ccf352b2
  6. Affected versionversion=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <c602cc344b4b8d41515fec3ffa98457ac963ee12
  7. Affected versionversion=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <e2d1ad207174a7cd7903dd27a00db4b2dfa6c64b
  8. Affected versionversion=5.10

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <385ddc0f008f24d1e7d03be998b3a98a37bd29ff; version=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <426358d9be7ce3518966422f87b96f1bad27295f; version=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <6d3275d4ca62e2c02e1b7e8cd32db59df91c14b7; version=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <9be29f8e7ce4e147e56caac2c3a0ce3573cf9c17; version=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <bbbd75346c8e6490b19c2ba90f38ea66ccf352b2; version=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <c602cc344b4b8d41515fec3ffa98457ac963ee12; version=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <e2d1ad207174a7cd7903dd27a00db4b2dfa6c64b; version=5.10
Siemens · RUGGEDCOM RST2428Pversion=0 <V4.0

Published CVSS scores

5.5Siemens ProductCERTCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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

CWE-20Improper Input Validation
T1499.004Application or System Exploitation

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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