Cyber Resilience

CVE-2026-33748

Path Traversal in Mobyproject Buildkit ≤ 0.28.1

Published
27 March 2026
Modified
20 April 2026
Patch / advisory
CVSS Score v4 8.2
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0046 38th percentile
Risk Priority 44 floored blend · peak EPSS

Summary

CVE-2026-33748 is a high-severity Path Traversal (CWE-22) vulnerability in Mobyproject Buildkit. Its CVSS base score is 8.2 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Path Interception (T1034); ranked at the 38th 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-2026-33748 is a path traversal vulnerability (CWE-22, CWE-59) in BuildKit, a toolkit for efficiently converting source code to build artifacts, affecting versions prior to 0.28.1. The flaw stems from insufficient validation of Git URL fragment subdir components during builds, which can enable access to files outside the checked-out Git repository root. Access is restricted to files on the same mounted filesystem. The vulnerability carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N), indicating high confidentiality impact with no requirements for privileges or user interaction.

The vulnerability can be exploited by any network-accessible attacker who can influence a BuildKit build process using a malicious Git URL containing a subpath (subdir) component. This typically occurs when building Dockerfiles from untrusted sources or Git repositories where the subdir points to a symlink. Successful exploitation allows the attacker to read sensitive files outside the intended repository context on the same filesystem, potentially exposing configuration data, credentials, or other host information during the build.

BuildKit addresses the issue in version v0.28.1, as detailed in the release notes and associated GitHub Security Advisory (GHSA-4vrq-3vrq-g6gg). As a workaround, practitioners should avoid building from untrusted Dockerfiles or Git repositories with untrusted subdir components. Additional context on Git URL fragments is available in Docker documentation.

OWASP Top 10 for Web (2025)

EU & UK References

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, insufficient validation of Git URL fragment subdir components may allow access to files outside the checked-out Git repository…

more

root. Possible access is limited to files on the same mounted filesystem. The issue has been fixed in version v0.28.1 The issue affects only builds that use Git URLs with a subpath component. As a workaround, avoid building Dockerfiles from untrusted sources or using the subdir component from an untrusted Git repository where the subdir component could point to a symlink.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1034 Path Interception Persistence
**This technique has been deprecated.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1547.009 Shortcut Modification Persistence
Adversaries may create or modify shortcuts that can execute a program during system boot or user login.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-23652Same product: Mobyproject Buildkit
CVE-2026-33747Same product: Mobyproject Buildkit
CVE-2026-24046Shared CWE-22, CWE-59
CVE-2026-44340Shared CWE-22, CWE-59
CVE-2026-34603Shared CWE-22, CWE-59
CVE-2026-47277Shared CWE-22, CWE-59
CVE-2022-21999Shared CWE-22, CWE-59
CVE-2026-33001Shared CWE-22, CWE-59
CVE-2026-34604Shared CWE-22, CWE-59
CVE-2026-42574Shared CWE-22, CWE-59

Affected Assets

mobyproject
buildkit
≤ 0.28.1

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V5.3.2
  • V15.4.2

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.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require code to validate paths and avoid unsafe link following.

PR.PS-02 partial match
prevents

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 none match
prevents

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.

finds

Security testing in development catches path traversal via static/dynamic analysis.

prevents

Secure SDLC mandates input validation and path sanitization that directly prevent path traversal.

prevents

Application security requirements include rules for safe file handling and canonicalization.

prevents

Secure architecture principles require least-privilege file access and directory isolation.

prevents

Secure coding standards explicitly forbid unsafe path construction and mandate safe APIs.

mitigates

Information access restriction limits which files an application may read or write.

References