Linux: Out-of-bounds Read
CVE-2026-23388 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 60f679f643f3f36a8571ea585e4ce5d93ef952b5, 3f68a9457a6190814377577374da75f872e0a013, 0c8ab092aec3ac4294940054772d30b511b16713 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.13% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 60f679f643f3f36a8571ea585e4ce5d93ef952b5 or 3f68a9457a6190814377577374da75f872e0a013 or 0c8ab092aec3ac4294940054772d30b511b16713 or 6b847d65f5b0065e02080c61fad93d57d6686383, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.253 or 5.15.203 or 6.1.167 or 6.6.130, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | f400e12656ab518be107febfe2315fb1eab5a342 up to, but not including, 60f679f643f3f36a8571ea585e4ce5d93ef952b5; f400e12656ab518be107febfe2315fb1eab5a342 up to, but not including, 3f68a9457a6190814377577374da75f872e0a013; f400e12656ab518be107febfe2315fb1eab5a342 up to, but not including, 0c8ab092aec3ac4294940054772d30b511b16713; f400e12656ab518be107febfe2315fb1eab5a342 up to, but not including, 6b847d65f5b0065e02080c61fad93d57d6686383; f400e12656ab518be107febfe2315fb1eab5a342 up to, but not including, 9e9fa5ad37c9cbad73c165c7ff1e76e650825e7c; f400e12656ab518be107febfe2315fb1eab5a342 up to, but not including, 01ee0bcc29864b78249308e8b35042b09bbf5fe3; f400e12656ab518be107febfe2315fb1eab5a342 up to, but not including, 3b9499e7d677dd4366239a292238489a804936b2; f400e12656ab518be107febfe2315fb1eab5a342 up to, but not including, fdb24a820a5832ec4532273282cbd4f22c291a0d; and 1 more ranges | 60f679f643f3f36a8571ea585e4ce5d93ef952b5, 3f68a9457a6190814377577374da75f872e0a013, 0c8ab092aec3ac4294940054772d30b511b16713, 6b847d65f5b0065e02080c61fad93d57d6686383, 9e9fa5ad37c9cbad73c165c7ff1e76e650825e7c, 01ee0bcc29864b78249308e8b35042b09bbf5fe3 |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | all versions | Not stated |
| Linux | Linux Kernel | 2.6.29.1 up to, but not including, 5.10.253; 5.11 up to, but not including, 5.15.203; 5.16 up to, but not including, 6.1.167; 6.2 up to, but not including, 6.6.130; 6.7 up to, but not including, 6.12.77; 6.13 up to, but not including, 6.18.17; 6.19 up to, but not including, 6.19.7; 2.6.29; and 1 more ranges | 5.10.253, 5.15.203, 6.1.167, 6.6.130, 6.12.77, 6.18.17 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H. Scored by NVD.
Official 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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that provides appropriate memory abstractions.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/01ee0bcc29864b78249308e8b35042b09bbf5fe3
- git.kernel.org/stable/c/0c8ab092aec3ac4294940054772d30b511b16713
- git.kernel.org/stable/c/3b9499e7d677dd4366239a292238489a804936b2
- git.kernel.org/stable/c/3f68a9457a6190814377577374da75f872e0a013
- git.kernel.org/stable/c/60f679f643f3f36a8571ea585e4ce5d93ef952b5
- git.kernel.org/stable/c/6b847d65f5b0065e02080c61fad93d57d6686383
- git.kernel.org/stable/c/9e9fa5ad37c9cbad73c165c7ff1e76e650825e7c
- git.kernel.org/stable/c/fdb24a820a5832ec4532273282cbd4f22c291a0d
Other references
Recent Out-of-bounds Read vulnerabilities
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
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