CVE-2026-23371: Linux kernel · sched/deadline: Fix missing ENQUEUE_REPLENISH during PI de-boosting
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
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 25 Mar 2026
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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10linuxpkg:deb/ubuntu/linux@6.17.0-40.40?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1019.19?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1020.20?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@6.17.0-1020.22?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1018.18?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 fix is available that addresses the issue by properly handling deadline parameter inheritance and setting the ENQUEUE_REPLENISH flag during priority class changes of DEADLINE tasks holding PI mutexes. Users should apply the official kernel updates that include this fix to affected versions. No additional mitigation is required beyond applying the patch.
Description
A vulnerability in the Linux kernel's SCHED_DEADLINE scheduler was fixed to address improper bandwidth accounting during priority inheritance (PI) de-boosting. The issue occurs when a DEADLINE task holding a PI mutex is changed to a lower priority class without properly inheriting deadline parameters from a donor task, causing missing ENQUEUE_REPLENISH flags and potential bandwidth accounting corruption. This can lead to warnings and instability under specific real-time scheduling conditions.
References
- ubuntu.com/security/CVE-2026-23371 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-23371 (opens in a new tab)
- git.kernel.org/linus/d658686a1331db3bb108ca079d76deb3208ed949 (opens in a new tab)
- git.kernel.org/stable/c/ba1c22924ddcc280672a2a06a9ca99ee3a1b92c3 (opens in a new tab)
- git.kernel.org/stable/c/d658686a1331db3bb108ca079d76deb3208ed949 (opens in a new tab)