CVE-2026-121520: Malicious client could set xattr value outside of BuildKit state directory
Medium · CVSS 4.5 (CVSS 4.0)EPSS 0.14%, 3th percentilePublished Updated Assigner: Docker
Description
In BuildKit versions prior to v0.34.1, a malicious client with access to the BuildKit control APIs can submit a build request that sets an extended attribute on a file outside the BuildKit state directory. Extended attributes in the trusted. or security. namespaces may also be set, potentially giving a program on the host elevated privileges. This issue affects build services that accept build requests from untrusted users. The issue is fixed in v0.34.1.
CWE-61
Tracked companies
Mapped from the CVE’s affected-product data, NVD CPE matches, vendor advisories or package feeds. A mapping means the vendor’s software is named, not that its hosted service was exposed.
Status incidents that name it
No tracked status incident names this CVE.
Affected vendors and products
Moby: BuildKit
References
- CVE record on cve.org (opens in new tab)
- NVD entry (opens in new tab)
- github.com/moby/buildkit/security/advisories/GHSA-w26x-xg27-7qjc (opens in new tab)
- CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (opens in new tab)
- This product uses data from the NVD API but is not endorsed or certified by the NVD. (opens in new tab)
- Known Exploited Vulnerabilities catalog from CISA. (opens in new tab)
- EPSS scores from FIRST (Exploit Prediction Scoring System). (opens in new tab)