VulnerabilityPublished 25 Sep 2026Updated 19 Oct 2026

CVE-2026-97902: Linux kernel · fs: don't return -EINVAL for successful nested thaw

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in ff2a694f6613d54ebd77ba72583d4d94446f55bd : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:05 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

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 ff2a694f6613d54ebd77ba72583d4d94446f55bd, fe967191e5851ea79818c5fe4e781c3882139218, 111339816138f042a59778322f941edc26903484 +1

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Sep 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 Linux kernel to ff2a694f6613d54ebd77ba72583d4d94446f55bd, fe967191e5851ea79818c5fe4e781c3882139218, 111339816138f042a59778322f941edc26903484 or 76e478499913dc1f368aebe85b28b7d1265985ff.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 7366f8b6fc6aa21c4199cb5d337b023df69745b0, < ff2a694f6613d54ebd77ba72583d4d94446f55bd	Fixed in ff2a694f6613d54ebd77ba72583d4d94446f55bd
LinuxLinux	Affected ≥ 7366f8b6fc6aa21c4199cb5d337b023df69745b0, < fe967191e5851ea79818c5fe4e781c3882139218	Fixed in fe967191e5851ea79818c5fe4e781c3882139218
LinuxLinux	Affected ≥ 7366f8b6fc6aa21c4199cb5d337b023df69745b0, < 111339816138f042a59778322f941edc26903484	Fixed in 111339816138f042a59778322f941edc26903484
LinuxLinux	Affected ≥ 7366f8b6fc6aa21c4199cb5d337b023df69745b0, < 76e478499913dc1f368aebe85b28b7d1265985ff	Fixed in 76e478499913dc1f368aebe85b28b7d1265985ff
LinuxLinux	Affected =6.8	Fixed in–

AI-suggested

A patch is available and has been applied in the Linux kernel versions identified by commits ff2a694f6613d54ebd77ba72583d4d94446f55bd, fe967191e5851ea79818c5fe4e781c3882139218, 111339816138f042a59778322f941edc26903484, and 76e478499913dc1f368aebe85b28b7d1265985ff. Users should update to a fixed kernel version to resolve this issue. Since this is a kernel-level fix, the vendor manages remediation for this cloud-hosted service if applicable. No additional mitigation is required beyond applying the official fix.

Description

A Linux kernel vulnerability in version 6.8 causes the thaw operation in nested filesystem freezes to incorrectly return an error code (-EINVAL) despite successfully releasing a freeze hold. This leads to a leaked freeze count on block devices when multiple freeze mechanisms are used, such as filesystem freeze (FIFREEZE) combined with block device freeze (bdev_freeze). The leak prevents the block device from being mounted again after unmounting, requiring a device destruction or system reboot to recover.

Impact

The impact is a persistent block device freeze state that prevents remounting the device after unmounting, effectively causing a denial of service for the affected block device. Userspace cannot drop the leaked freeze count, and recovery requires destroying the block device or rebooting the system. This affects setups using nested freezes, such as device-mapper volumes or LVM snapshots, potentially disrupting storage availability.

Summary

The vulnerability in the Linux kernel's filesystem freeze/thaw mechanism arises from a logic change in commit 7366f8b6fc6a, which replaced a freeze_holders bitmask with per-holder counters to support nested freezes. The thaw_super_locked() function drops the freeze reference but returns -EINVAL if other freezers remain, incorrectly signaling failure to the caller. This causes bdev_thaw() to keep the block device freeze count elevated, resulting in a permanent freeze state on the block device after unmounting. This affects scenarios where the filesystem is frozen via FIFREEZE and additionally frozen via bdev_freeze(), such as with device-mapper or LVM snapshots. The issue is fixed by restoring the correct return value (0) when a nested thaw drops its hold but other freezers remain, aligning with documented intended semantics.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 13:36 UTC

Technical details

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