CVE-2025-68333: Linux kernel · sched_ext: Fix possible deadlock in the deferred_irq_workfn()
Affects Linux kernelSource GCVE Database
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, 14:05 UTC
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 22 Dec 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10linuxpkg:deb/ubuntu/linux@6.17.0-19.19?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1009.9?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1010.10?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp@6.17.0-1009.9?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1009.9?arch=source&distro=questingOther threats | Affected
| Fixed in
|
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
- ubuntu.com/security/CVE-2025-68333 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-68333 (opens in a new tab)
- git.kernel.org/stable/c/600b4379b9a7ba41340d652211fb29699da4c629 (opens in a new tab)
- git.kernel.org/stable/c/a257e974210320ede524f340ffe16bf4bf0dda1e (opens in a new tab)
- ubuntu.com/security/notices/USN-8094-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8094-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8094-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8094-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8094-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8152-1 (opens in a new tab)