# CVE-2021-41072: Path traversal in n/a

> Crafted squashfs filesystems allow unsquashfs to write files outside the target directory via symbolic link traversal, potentially modifying arbitrary files.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 14 Sep 2021
- **Updated:** 4 Aug 2024
- **Also known as:** ALPINE-CVE-2021-41072, AZL-7464, CLSA-2025-1751888935, DEBIAN-CVE-2021-41072, DLA-2789-1, DSA-4987-1, GHSA-f6m6-9fjw-69qm, UBUNTU-CVE-2021-41072, USN-5078-1, USN-5078-3, openSUSE-SU-2024:11986-1

## What is CVE-2021-41072?

CVE-2021-41072 is a high-severity path traversal vulnerability in Debian Debian Linux, published on 14 Sep 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official 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.

Weakness: CWE-59 (Improper Link Resolution Before File Access), CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2021-41072?

It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `squashfs` | openSUSE:Tumbleweed | All versions | 4.5.1-1.1 |

Products: Debian Debian Linux, Squashfs-Tools Project Squashfs-Tools.

## How do I fix CVE-2021-41072?

Apply the vendor's patch.

## Is CVE-2021-41072 being exploited?

There is no known exploitation of CVE-2021-41072 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-41072 and fix it if it is affected.

What it is: CVE-2021-41072 is a high-severity path traversal vulnerability in Debian Debian Linux, published on 14 Sep 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-41072 in the wild and no public exploit code.

Affected product: Debian Debian Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-41072/ (Markdown: https://insights.sbomify.com/CVE-2021-41072/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-41072
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-41072
- OSV: https://osv.dev/vulnerability/CVE-2021-41072

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-41072/
Summaries are generated and may contain mistakes; the official description above is the record.