Path traversal in BuildKit - CVE-2026-33747
Published: April 28, 2026
Vulnerability identifier: #VU128396
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-33747
CWE-ID: CWE-22
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Moby project
Affected software:
BuildKit
BuildKit
Detailed vulnerability description
The vulnerability allows a remote attacker to write files outside of the BuildKit state directory.
The vulnerability exists due to improper path restriction in custom BuildKit frontend API message handling when processing a crafted API message from a custom frontend. A remote attacker can craft an API message to write files outside of the BuildKit state directory.
Exploitation requires use of an untrusted custom frontend configured with #syntax or --build-arg BUILDKIT_SYNTAX.
How to mitigate CVE-2026-33747
Install security update from vendor's website.