# CVE-2020-28949: PEAR Archive_Tar Deserialization of Untrusted Data

> Attackers can overwrite arbitrary files via stream wrapper attacks in the Archive_Tar library due to insufficient filename sanitization.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Yes, since 25 Aug 2022 (CISA KEV)
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 19 Nov 2020
- **Updated:** 21 Oct 2025
- **Also known as:** CLEANSTART-2024-ZN01309, DEBIAN-CVE-2020-28949, UBUNTU-CVE-2020-28949

## What is CVE-2020-28949?

CVE-2020-28949 is a high-severity path traversal vulnerability in Debian Debian Linux, published on 19 Nov 2020. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

Archive_Tar through 1.4.10 has :// filename sanitization only to address phar attacks, and thus any other stream-wrapper attack (such as file:// to overwrite files) can still succeed.

## Which versions are affected by CVE-2020-28949?

It affects 4 products.


Products: Debian Debian Linux, Drupal Drupal, Fedoraproject Fedora, Php Archive Tar.

## How do I fix CVE-2020-28949?

Upgrade to a fixed version. US federal agencies must fix it by 15 Sep 2022.

## Is CVE-2020-28949 being exploited?

Yes. Attackers have exploited CVE-2020-28949 in the wild since at least 25 Aug 2022.

Public exploit code:

- PEAR Archive_Tar 1.4.10 Arbitrary File Write (metasploit)

## 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-2020-28949 and fix it if it is affected.

What it is: CVE-2020-28949 is a high-severity path traversal vulnerability in Debian Debian Linux, published on 19 Nov 2020. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: Yes. Attackers have exploited CVE-2020-28949 in the wild since at least 25 Aug 2022.

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-2020-28949/ (Markdown: https://insights.sbomify.com/CVE-2020-28949/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-28949
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-28949
- OSV: https://osv.dev/vulnerability/CVE-2020-28949

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-28949/
Summaries are generated and may contain mistakes; the official description above is the record.