---
title: "CVE-2026-82331: Apache BuildStream - Path Traversal"
description: "Apache BuildStream < 2.8.1 on Python < 3.12 contains a file write vulnerability caused by improper link resolution in the tar source plugin, letting attackers write files via symlinks during source fetching, exploit requires malicious source tarballs."
url: https://panop.io/threat-heartbeat/CVE-2026-82331/
---

# CVE-2026-82331 Apache BuildStream - Path Traversal

Apache BuildStream < 2.8.1 on Python < 3.12 contains a file write vulnerability caused by improper link resolution in the tar source plugin, letting attackers write files via symlinks during source fetching, exploit requires malicious source tarballs.

CVSS base score 9.8 /10

Critical

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.42% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-82331)

## Details

Type

Path Traversal

Impact

File System Write, Data Tampering

CVSS vector

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

Published

23 September 2026

Updated

15 October 2026

Weakness

[CWE-59](https://cwe.mitre.org/data/definitions/59.html)

## Vendor fix

Upgrade to version 2.8.1 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-82331](https://nvd.nist.gov/vuln/detail/CVE-2026-82331)
- [http://www.openwall.com/lists/oss-security/2026/09/23/9](http://www.openwall.com/lists/oss-security/2026/09/23/9)
- [https://lists.apache.org/thread/9b342631x7bvtyg0pq7zgywtl2cmy34v](https://lists.apache.org/thread/9b342631x7bvtyg0pq7zgywtl2cmy34v)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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