CVE-2026-121520

medium

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.

References

https://github.com/moby/buildkit/security/advisories/GHSA-w26x-xg27-7qjc

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-116538

Details

Source: Mitre, NVD

Published: 2026-11-03

Updated: 2026-11-03

Risk Information

CVSS v2

Base Score: 7.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

Severity: High

CVSS v3

Base Score: 9.8

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: Critical

CVSS v4

Base Score: 4.5

Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:N/SC:N/SI:H/SA:H

Severity: Medium

EPSS

EPSS: 0.00139