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VulnerabilityPublished Updated

CVE-2025-68333: Linux kernel · sched_ext: Fix possible deadlock in the deferred_irq_workfn()

Affects Linux kernelSource GCVE Database

0

Not known to be exploited · CVSS 5.5 Medium · fixed in 6.17.0-1009.9~24.04.2 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 15:59 UTC

CVSS 3.1 base score
5.5Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 6.17.0-1009.9~24.04.2, 6.17.0-1010.10~24.04.1, 6.17.0-1009.9~24.04.3 +11
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 22 Dec 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 to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Ubuntu 25.10linuxpkg:deb/ubuntu/linux@6.17.0-19.19?arch=source&distro=questingOther threatsAffected
  • <6.17.0-19.19
Fixed in
  • 6.17.0-19.19
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1009.9?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1009.9
Fixed in
  • 6.17.0-1009.9
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1010.10?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1010.10
Fixed in
  • 6.17.0-1010.10
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threatsAffected
  • 6.17.0-1003.3 – 6.17.0-1017.17
10 affected builds
Fixed in–
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp@6.17.0-1009.9?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1009.9
Fixed in
  • 6.17.0-1009.9
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1009.9?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1009.9
Fixed in
  • 6.17.0-1009.9

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available and should be applied to affected Linux kernel versions. The fix is included in Linux kernel updates starting with versions 6.17.0-1009.9~24.04.2 and related builds. Users should update their kernels to these or later versions to resolve the deadlock issue. No additional mitigation actions are required beyond applying the official patch.

Description

A deadlock vulnerability in the Linux kernel's sched_ext subsystem was fixed for PREEMPT_RT=y kernels. The issue involved the deferred_irq_workfn() function potentially causing a deadlock due to improper locking behavior in per-CPU irq_work task context. This was resolved by changing the initialization to ensure the function is always invoked in hard-irq context. The vulnerability affects certain Linux kernel versions prior to 6.17.0-1009.9~24.04.2 and related versions. A patch is available as part of the Linux kernel updates.

References

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