CVE-2021-40153: Debian Linux

High severity, CVSS 8.1. EPSS: 2.5% chance of exploitation in the next 30 days.

squashfs_opendir in unsquash-1.c in Squashfs-Tools 4.5 stores the filename in the directory entry; this is then used by unsquashfs to create the new file during the unsquash. The filename is not validated for traversal outside of the destination directory, and thus allows writing to locations outside of the destination.

Affected products

• Debian Debian Linux: version 9.0 only; version 10.0 only
• Fedoraproject Fedora: version 34 only; version 33 only
• Red Hat Enterprise Linux: version 7.0 only; version 8.0 only
• Squashfs-Tools Project Squashfs-Tools: version 4.5 only

Published 2021-08-27. Last modified 2026-06-17.