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VulnerabilityPublished Updated

CVE-2025-71126: Linux kernel · mptcp: avoid deadlock on fallback while reinjecting

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.5 High · fixed in ffb8c27b0539dd90262d1021488e7817fae57c42 : patch Linux kernel soon.

Data as of 26 Oct 2026, 12:55 UTC

CVSS 3.1 base score
7.5High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 18% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers can reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in ffb8c27b0539dd90262d1021488e7817fae57c42, 252892d5a6a2f163ce18f32716e46fa4da7d4e79, 0107442e82c0f8d6010e07e6030741c59c520d6e +6
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 14 Jan 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • >=6.1.149 <6.1.160
  • >=6.6.101 <6.6.120
  • >=6.12.40 <6.12.64
  • >=6.15.8 <6.16
Fixed in
  • ffb8c27b0539dd90262d1021488e7817fae57c42
  • 252892d5a6a2f163ce18f32716e46fa4da7d4e79
  • 0107442e82c0f8d6010e07e6030741c59c520d6e
  • 50f47c02be419bf0a3ae94c118addf67beef359f
  • 6.16
  • 6.12.64
  • 6.6.120
  • 6.1.160
  • 0ca9fb4335e726dab4f23b3bfe87271d8f005f41
LinuxLinuxAffected
  • =6.16
Fixed in–

AI-suggested

A fix is available and has been applied in Linux kernel versions 6.1.160, 6.6.120, 6.12.64, and 6.16. Users and administrators should upgrade to these or later kernel versions to remediate the issue. No additional mitigation actions are required beyond applying the official patches.

Description

CVE-2025-71126 is a high-severity vulnerability in the Linux kernel's Multipath TCP (MPTCP) implementation that can cause a deadlock during fallback reinjection. The issue arises when the packet scheduler attempts reinjection after receiving an MP_FAIL before the infinite map is transmitted, leading to recursive locking and a deadlock. This flaw affects multiple Linux kernel versions prior to 6.1.160, 6.6.120, 6.12.64, and 6.16, and has been fixed in these versions.

References

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