Bug 2451212 (CVE-2026-23388)

Summary: CVE-2026-23388 kernel: Squashfs: check metadata block offset is within range
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in the Linux kernel's Squashfs component. A local attacker could craft a malicious Squashfs image with a corrupted index look-up table, leading to a negative metadata block offset. This negative offset causes an out-of-bounds access when processing the image, resulting in a general protection fault and a system crash, effectively causing a Denial of Service (DoS).
 Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-03-25 11:04:57 UTC 
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.
Comment 1 Alexander B 2026-03-25 15:39:14 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026032544-CVE-2026-23388-9e71@gregkh/T