Link Following Affecting buildstream package, versions <2.8.1-1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-DEBIANUNSTABLE-BUILDSTREAM-20066583
- published24 Sept 2026
- disclosed23 Sept 2026
Introduced: 23 Sep 2026
NewCVE-2026-82331 (opens in a new tab)How to fix?
Upgrade Debian:unstable buildstream to version 2.8.1-1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream buildstream package and not the buildstream package as distributed by Debian.
See How to fix? for Debian:unstable relevant fixed versions and status.
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
tarfilefilter functionality, which blocks the symlink escape
Users are recommended to upgrade to version 2.8.1, which fixes this issue.