🛡️ CVE-2021-40153 on Debian — squashfs-tools

⚪ Unknown ✅ No Known Exploit OSV

N/A

CVSS Score

0 Low4 Medium7 High9 Critical10

Description

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.

Distribution advisory

This page covers CVE-2021-40153 as tracked by Debian, for the package squashfs-tools. The fix is available in version 1:4.5-2; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. A user must be tricked into taking some action. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity high, availability high.

Affected software

DEBIAN-CVE-2021-40153 is recorded against 1 package.

squashfs-tools (fixed in 1:4.5-2)

Timeline and source

Published on 27 August 2021 and last revised on 4 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

CVE-2021-40153 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Alpine Ubuntu

Details

Severity Unknown

CVSS Score N/A

CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H

CWE N/A

Public Exploit ✅ No

Source OSV

Published 2021-08-27

Updated 2026-08-12

Modified 2026-08-04

Fix URL N/A

Affected Packages

Software	From version	Fixed in
squashfs-tools	—	1:4.5-2

References

ADVISORY https://security-tracker.debian.org/tracker/CVE-2021-40153

🔗 NVD 🔗 Mitre

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