CVE-2026-82331

buildstream: Improper link resolution before file access ('link following') vulnerability in the `tar` source plugin of Apache Bui...

CVE-2026-82331 is fixed in buildstream on 1 platform, first by DEBIAN-CVE-2026-82331, released September 26, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

Urgent
CVSS
9.8
critical
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0041
35th percentile

Improper link resolution before file access ('link following') vulnerability in the `tar` source plugin of Apache BuildStream running on Python < 3.12 allows malicious source tarballs to write files on the host, with the privileges of the user running BuildStream, via symlinks as part of source fetching. The impact of this issue is mitigated by: * BuildStream projects should only use trusted sources in their elements as otherwise the build output can also not be trusted * Tracking a source tarball pins its SHA256 hash, which prevents MITM attacks of users that are fetching an already tracked project * When running on Python >= 3.12, BuildStream >= 2.3.0 already makes use of the Python `tarfile` filter functionality, which blocks the symlink escape Users are recommended to upgrade to version 2.8.1, which fixes this issue.

Where it's fixed

ProductFixed inFixReleased
Linux
buildstream · Debian 13.5 (trixie) 1.6.9-2+deb13u1 DEBIAN-CVE-2026-82331 Sep 26, 2026
buildstream · Debian 14 2.8.1-1 DEBIAN-CVE-2026-82331 Sep 26, 2026

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