VulnerabilityPublished 13 Jan 2026Updated 14 Oct 2026

CVE-2025-68780: Linux kernel · sched/deadline: only set free_cpus for online runqueues

Affects Linux kernelSource GCVE Database

Not known to be exploited · fixed in 5.15.0-1103.110~20.04.1 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 17:16 UTC

Severity

Medium

Rated by Threat Radar · No CVSS score from NVD or the CNA

EPSS: 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 5.15.0-1103.110~20.04.1, 5.15.0-1110.119~20.04.1, 5.15.0-1114.123~20.04.1 +75

Exploitation evidence

Disclosed: evidence found.
CVE published 13 Jan 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.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
Ubuntu 25.10linux`pkg:deb/ubuntu/linux?arch=source&distro=questing`Other threats	Affected <6.17.0-22.22	Fixed in 6.17.0-22.22
Ubuntu 25.10linux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=questing`Other threats	Affected <6.17.0-1012.12	Fixed in 6.17.0-1012.12
Ubuntu 25.10linux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=questing`Other threats	Affected <6.17.0-1013.13	Fixed in 6.17.0-1013.13
Ubuntu 25.10linux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questing`Other threats	Affected 6.17.0-1003.3 – 6.17.0-1017.17 10 affected builds	Fixed in–
Ubuntu 25.10linux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=questing`Other threats	Affected <6.17.0-1012.12	Fixed in 6.17.0-1012.12
Ubuntu 25.10linux-oracle`pkg:deb/ubuntu/linux-oracle?arch=source&distro=questing`Other threats	Affected <6.17.0-1011.11	Fixed in 6.17.0-1011.11

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

AI-suggested

An official fix is available and has been released in Linux kernel versions that address this issue. Users should update to the patched kernel versions to ensure the free_cpus mask correctly reflects CPU online states. The vendor advisory confirms the flaw is corrected in updated kernel releases. No additional mitigation steps are indicated.

Description

A vulnerability in the Linux kernel's deadline scheduler was resolved by modifying how the free_cpus mask is set for online runqueues. The issue could cause the scheduler to incorrectly mark CPUs as available when they are offline, potentially leading to deadline tasks being assigned to CPUs that cannot run them. This flaw was fixed by ensuring the free_cpus mask accurately reflects the online state of runqueues and removing redundant mask management functions.

Impact

If exploited, this vulnerability could cause deadline tasks to be assigned to CPUs that are offline, resulting in those tasks not running as expected. This could lead to degraded system performance or denial of service for time-sensitive tasks relying on the deadline scheduler. There is no indication of privilege escalation or remote exploitation in the provided data.

Summary

The Linux kernel vulnerability (CVE-2025-68780) involves the deadline scheduler's cpudl::free_cpus mask, which could incorrectly indicate that an offline CPU is free. This occurs because the cpudl_clear function could set the free_cpus bit for a CPU even when its deadline runqueue is offline. Consequently, a deadline task might be pushed to a powered-down CPU, preventing the task from running. The fix modifies cpudl_clear to consider the online state of the deadline runqueue, ensuring the free_cpus mask is updated correctly under the cpudl lock and removing the now unnecessary cpudl_set/clear_freecpu functions.

GCVE source: db.gcve.eu
OSV ID: UBUNTU-CVE-2025-68780
Osv Schema Version: 1.7.0
Ecosystems: Ubuntu:Pro:14.04:LTS, Ubuntu:Pro:16.04:LTS, Ubuntu:16.04:LTS, Ubuntu:Pro:FIPS:16.04:LTS, Ubuntu:Pro:18.04:LTS, Ubuntu:18.04:LTS, Ubuntu:Pro:FIPS-updates:18.04:LTS, Ubuntu:Pro:FIPS:18.04:LTS, Ubuntu:Pro:20.04:LTS, Ubuntu:20.04:LTS, Ubuntu:Pro:FIPS-updates:20.04:LTS, Ubuntu:Pro:FIPS:20.04:LTS, Ubuntu:22.04:LTS, Ubuntu:Nvidia-BlueField:22.04:LTS, Ubuntu:Pro:FIPS-preview:22.04:LTS, Ubuntu:Pro:FIPS-updates:22.04:LTS, Ubuntu:Pro:Realtime:22.04:LTS, Ubuntu:24.04:LTS, Ubuntu:Nvidia-BlueField:24.04:LTS, Ubuntu:Pro:FIPS-updates:24.04:LTS, Ubuntu:Pro:Realtime:24.04:LTS, Ubuntu:25.10

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 15 Sep 2026, 14:17 UTC

Technical details

References

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