VulnerabilityPublished 25 Mar 2026Updated 5 Nov 2026

CVE-2026-23388: Linux kernel · Squashfs: check metadata block offset is within range

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in fdb24a820a5832ec4532273282cbd4f22c291a0d : update Linux kernel when convenient.

Data as of 5 Nov 2026, 21:49 UTC

Severity

Unrated

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

Thin evidence

One scorer or none

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-05.

Patch

Available – fixed in fdb24a820a5832ec4532273282cbd4f22c291a0d, 60f679f643f3f36a8571ea585e4ce5d93ef952b5, 9e9fa5ad37c9cbad73c165c7ff1e76e650825e7c +5

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 5 Nov 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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
LinuxLinux	Affected ≥ f400e12656ab518be107febfe2315fb1eab5a342, < fdb24a820a5832ec4532273282cbd4f22c291a0d	Fixed in fdb24a820a5832ec4532273282cbd4f22c291a0d
LinuxLinux	Affected ≥ f400e12656ab518be107febfe2315fb1eab5a342, < 60f679f643f3f36a8571ea585e4ce5d93ef952b5	Fixed in 60f679f643f3f36a8571ea585e4ce5d93ef952b5
LinuxLinux	Affected ≥ f400e12656ab518be107febfe2315fb1eab5a342, < 9e9fa5ad37c9cbad73c165c7ff1e76e650825e7c	Fixed in 9e9fa5ad37c9cbad73c165c7ff1e76e650825e7c
LinuxLinux	Affected ≥ f400e12656ab518be107febfe2315fb1eab5a342, < 6b847d65f5b0065e02080c61fad93d57d6686383	Fixed in 6b847d65f5b0065e02080c61fad93d57d6686383
LinuxLinux	Affected ≥ f400e12656ab518be107febfe2315fb1eab5a342, < 3f68a9457a6190814377577374da75f872e0a013	Fixed in 3f68a9457a6190814377577374da75f872e0a013
LinuxLinux	Affected ≥ f400e12656ab518be107febfe2315fb1eab5a342, < 3b9499e7d677dd4366239a292238489a804936b2	Fixed in 3b9499e7d677dd4366239a292238489a804936b2

Description

In the Linux kernel, the following vulnerability has been resolved: Squashfs: check metadata block offset is within range Syzkaller reports a "general protection fault in squashfs_copy_data" This is ultimately caused by a corrupted index look-up table, which produces a negative metadata block offset. This is subsequently passed to squashfs_copy_data (via squashfs_read_metadata) where the negative offset causes an out of bounds access. The fix is to check that the offset is within range in squashfs_read_metadata. This will trap this and other cases.

References

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