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Malicious frontend can cause file escape outside of storage root

High
tonistiigi published GHSA-4c29-8rgm-jvjj Mar 25, 2026

Package

No package listed

Affected versions

<= v0.28.0

Patched versions

v0.28.1+

Description

Impact

When using a custom BuildKit frontend, the frontend can craft an API message that causes files to be written outside of the BuildKit state directory for the execution context.

Patches

The issue has been fixed in v0.28.1+

Workarounds

Issue requires using an untrusted BuildKit frontend set with #syntax or --build-arg BUILDKIT_SYNTAX. Using these options with a well-known frontend image like docker/dockerfile is not affected.

References

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVE ID

CVE-2026-33747

Weaknesses

No CWEs

Credits