CVE Catalog

CVE-2026-82331

CriticalCVSS 9.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.20%

10th percentile - higher than 10% of all known CVEs

Summary

A link following vulnerability in the `tar` source plugin of Apache BuildStream running on Python < 3.12. Malicious source tarballs can write files on the host with the privileges of the user running BuildStream via symlinks during source fetching.

Risk Assessment

An attacker may overwrite or create files on the host system, potentially compromising the integrity of the build environment or performing unauthorized file operations.

Recommendation

Upgrade BuildStream to version 2.8.1, which fixes this issue; only use trusted sources in your projects.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS