Critical 9.8Published Sep 23, 2026

CVE-2026-82331Apache BuildStream: tar source extraction escape

Updated under an hour ago (2026-10-19 07:30 UTC)

Does this affect you?

It affects Apache Software Foundation Apache BuildStream. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for Apache Software Foundation Apache BuildStream

Exploited in the last 30 days

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.

CVSS: 9.8 CRITICAL (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-59
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: apache
NVD analysis: Awaiting Analysis
Record last updated: Sep 23, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Apache Software Foundation Apache BuildStream apache_software_foundation:apache_buildstream (from the name)	through 2.8.0; 2.8.1 not affected	CNA record

References

https://lists.apache.org/thread/9b342631x7bvtyg0pq7zgywtl2cmy34vvendor-advisory
http://www.openwall.com/lists/oss-security/2026/09/23/9

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.