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VulnerabilityPublished Updated

CVE-2025-39976: Linux kernel · futex: Use correct exit on failure from futex_hash_allocate_default()

Affects Linux kernelSource GCVE Database

0

Not known to be exploited · CVSS 7.8 High · fixed in 6.17.0-1006.6 : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 6.17.0-1006.6, 6.17.0-1003.3, 6.17.0-6.6
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 15 Oct 2025

  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 Linux kernel to 6.17.0-1006.6, 6.17.0-1003.3 or 6.17.0-6.6.

Affected software

ProductAffectedFixed in
linux-hwe-edgeAffected
  • <6.17.0-6.6
  • <6.17.0-1003.3
  • <6.17.0-1006.6
Fixed in
  • 6.17.0-6.6
  • 6.17.0-1003.3
  • 6.17.0-1006.6

AI-suggested

A fix for this vulnerability has been implemented in the Linux kernel by correcting the error exit path in copy_process() to use the proper label. Users should apply the official kernel updates or patches that include this fix. Since no vendor advisory or patch links are provided here, check the official Linux kernel repositories or vendor advisories for the specific patch and update instructions.

Description

In the Linux kernel, the following vulnerability has been resolved: futex: Use correct exit on failure from futex_hash_allocate_default() copy_process() uses the wrong error exit path from futex_hash_allocate_default(). After exiting from futex_hash_allocate_default(), neither tasklist_lock nor siglock has been acquired. The exit label bad_fork_core_free unlocks both of these locks which is wrong. The next exit label, bad_fork_cancel_cgroup, is the correct exit. sched_cgroup_fork() did not allocate any resources that need to freed. Use bad_fork_cancel_cgroup on error exit from futex_hash_allocate_default().

References

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