Raw vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2026-33747 is a high-severity Path Traversal (CWE-22) vulnerability in Mobyproject Buildkit. Its CVSS base score is 8.4 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 40th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-33747 is a path traversal vulnerability (CWE-22) in BuildKit, a toolkit for efficiently converting source code to build artifacts. The flaw affects versions prior to 0.28.1 and occurs when using a custom BuildKit frontend specified via `#syntax` directives or the `--build-arg BUILDKIT_SYNTAX` option. In such cases, a malicious frontend can craft an API message that writes files outside the intended BuildKit state directory for the execution context. Well-known frontends like `docker/dockerfile` are explicitly not affected.
The vulnerability has a CVSS v3.1 base score of 8.4 (AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating high impact with low attack complexity and no privileges required. A local attacker who controls or influences a custom, untrusted BuildKit frontend can exploit it during the build process to overwrite or create arbitrary files outside the sandboxed state directory, potentially leading to full system compromise through privilege escalation, data corruption, or denial of service.
The issue was addressed in BuildKit version 0.28.1, as detailed in the project's release notes and security advisory. Users should upgrade to v0.28.1 or later and avoid untrusted custom frontends when possible. Relevant resources include the release announcement at https://github.com/moby/buildkit/releases/tag/v0.28.1 and the GitHub Security Advisory at https://github.com/moby/buildkit/security/advisories/GHSA-4c29-8rgm-jvjj.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-16518
Vulnerability Data
BuildKit is a toolkit for converting source code to build artifacts in an efficient, expressive and repeatable manner. Prior to version 0.28.1, when using a custom BuildKit frontend, the frontend can craft an API message that causes files to be…
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written outside of the BuildKit state directory for the execution context. The issue has been fixed in v0.28.1. The vulnerability 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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.3.2
Mitigating Controls (NIST 800-53 r5) AI
Enforces the intended directory access authorizations that path traversal would otherwise bypass.
Input validation directly neutralizes special path elements before pathname construction occurs.
Least privilege reduces the impact of any unauthorized file access obtained via traversal.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Patching/maintenance can remediate known path-traversal flaws in deployed software (partial prevention of exploitability) but does nothing to stop the coding defect from being introduced in the first place.
PR.AA-05 defines and reviews access policies but does not address code-level pathname neutralization, so neither direction prevents CWE-22.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development catches path traversal via static/dynamic analysis.
Secure SDLC mandates input validation and path sanitization that directly prevent path traversal.
Application security requirements include rules for safe file handling and canonicalization.
Secure architecture principles require least-privilege file access and directory isolation.
Secure coding standards explicitly forbid unsafe path construction and mandate safe APIs.
Information access restriction limits which files an application may read or write.