CVE-2026-121520
Published:November 03, 2026
Updated:November 04, 2026
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.
Affected Packages
https://github.com/moby/buildkit.git (GITHUB):
Affected version(s) >=v0.3.0 <v0.34.2Fix Suggestion:
Update to version v0.34.2github.com/moby/buildkit (GO):
Affected version(s) >=v0.3.0 <v0.34.2Fix Suggestion:
Update to version v0.34.2Related Resources (4)
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Contact UsCVSS v4
Base Score:
4.5
Attack Vector
LOCAL
Attack Complexity
LOW
Attack Requirements
PRESENT
Privileges Required
HIGH
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
HIGH
Subsequent System Availability
HIGH
CVSS v3
Base Score:
7.9
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
CHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
HIGH
Weakness Type (CWE)
UNIX Symbolic Link (Symlink) Following