Apache BuildStream security advisories

Security information for Apache BuildStream

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Advisories

This section is experimental: it provides advisories since 2023 and may lag behind the official CVE publications. If you have any feedback on how you would like this data to be provided, you are welcome to reach out on our public mailinglist or privately on security@apache.org

tar source extraction escape

CVE-2026-82331 [CVE] [CVE json] [OSV json]

Last updated: 2026-10-05T12:06:14.531Z

Affected

  • Apache BuildStream through 2.8.0

Description

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.

References

Credits

  • Gjoko Krstic of Zero Science Lab (finder)