VulnerabilityPublished 13 Jan 2026Updated 31 Jul 2026

CVE-2025-68771: Linux kernel · ocfs2: fix kernel BUG in ocfs2_find_victim_chain

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, 14:05 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 +71

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@6.17.0-22.22?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@6.17.0-1012.12?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@6.17.0-1013.13?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@6.17.0-1017.17?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@6.17.0-1012.12?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@6.17.0-1011.11?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

A patch is available and should be applied to affected Linux kernel versions. The fix prevents kernel panics by handling invalid allocation chain states gracefully. Users should update to the fixed kernel versions as per the vendor advisory.

Description

A kernel bug in the Linux ocfs2 filesystem driver was fixed to prevent kernel panics caused by invalid allocation chain list states. The issue occurred when the cl_next_free_rec field was zero or out of range, triggering a kernel BUG and panic. The fix introduces a check that logs an error instead of panicking when no free chains remain. This vulnerability affects certain Linux kernel versions prior to specific 5.15.x updates. The issue is medium severity and has been patched.

Impact

The vulnerability could cause a kernel panic leading to denial of service on affected Linux systems running vulnerable ocfs2 filesystem code. There is no indication of privilege escalation or information disclosure. The impact is limited to system stability disruption.

Summary

The Linux kernel ocfs2 filesystem had a vulnerability where the ocfs2_find_victim_chain() function could trigger a kernel BUG and panic if the cl_next_free_rec field in the allocation chain list was zero or greater than the total chain count. This condition indicated no free chains were available, but the kernel would panic due to a BUG_ON() assertion. The fix adds a conditional check in ocfs2_claim_suballoc_bits() to detect these conditions and invoke ocfs2_error() to log the error instead of panicking, improving stability and preventing denial of service via kernel panic.

GCVE source: db.gcve.eu
OSV ID: UBUNTU-CVE-2025-68771
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, 12:52 UTC

Technical details

References

Community reviews

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