CVE-2026-23388: Linux kernel · Squashfs: check metadata block offset is within range
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.1 High · patch available : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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 patch is available for this vulnerability and should be applied by updating to the fixed Linux kernel versions. The vendor advisory from Ubuntu confirms that this issue has been addressed in security updates. Users should apply the official kernel updates provided by their distribution to remediate this vulnerability.
Description
A vulnerability in the Linux kernel's Squashfs filesystem was resolved by adding a check to ensure metadata block offsets are within valid ranges. The issue was caused by a corrupted index look-up table producing negative metadata block offsets, leading to out-of-bounds memory access in squashfs_copy_data. This flaw could be triggered locally and has a medium severity rating with a CVSS score of 7.1. Multiple specific Linux kernel versions are affected. A patch is available and has been incorporated in Linux kernel updates.
References
- ubuntu.com/security/CVE-2026-23388 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-23388 (opens in a new tab)
- git.kernel.org/linus/fdb24a820a5832ec4532273282cbd4f22c291a0d (opens in a new tab)
- git.kernel.org/stable/c/01ee0bcc29864b78249308e8b35042b09bbf5fe3 (opens in a new tab)
- git.kernel.org/stable/c/0c8ab092aec3ac4294940054772d30b511b16713 (opens in a new tab)
- git.kernel.org/stable/c/3b9499e7d677dd4366239a292238489a804936b2 (opens in a new tab)
- git.kernel.org/stable/c/6b847d65f5b0065e02080c61fad93d57d6686383 (opens in a new tab)
- git.kernel.org/stable/c/9e9fa5ad37c9cbad73c165c7ff1e76e650825e7c (opens in a new tab)
- git.kernel.org/stable/c/fdb24a820a5832ec4532273282cbd4f22c291a0d (opens in a new tab)
- ubuntu.com/security/notices/USN-8567-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8576-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8595-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8596-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8576-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8597-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8595-2 (opens in a new tab)