{"id":"CVE-2026-82331","published":"2026-09-23T07:16:46.493","lastModified":"2026-09-23T17:58:26.570","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.\nThe impact of this issue is mitigated by:\n\n* BuildStream projects should only use trusted sources in their elements as otherwise the build output can also not be trusted\n* Tracking a source tarball pins its SHA256 hash, which prevents MITM attacks of users that are fetching an already tracked project\n* When running on Python >= 3.12, BuildStream >= 2.3.0 already makes use of the Python `tarfile` filter functionality, which blocks the symlink escape\n\nUsers are recommended to upgrade to version 2.8.1, which fixes this issue.","cvssScore":9.8,"cvssSeverity":"CRITICAL","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwes":["CWE-59"],"vendors":[],"products":[],"references":[{"url":"https://lists.apache.org/thread/9b342631x7bvtyg0pq7zgywtl2cmy34v","tags":[]},{"url":"http://www.openwall.com/lists/oss-security/2026/09/23/9","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":{"summary":"This flaw allows malicious source tarballs to write files on the host, posing a critical risk due to potential privilege escalation.","exploitability":"Exploitation is moderately hard as it requires a malicious source tarball and the use of symlinks, but is feasible under certain conditions.","blast_radius":"If exploited, the impact is severe, as it can lead to unauthorized file writes and potential privilege escalation on the host system.","remediation":"Upgrade to BuildStream version 2.8.1 or later.","detection":"No reliable host or network indicator is derivable from the published description.","tags":["rce","file-write","priv-escalation","python","buildstream"],"model":"qwen2.5:7b-instruct","analyzedAt":"2026-09-27T08:50:41.805Z"}}