Quick answer
Direct answer
Risk scores
| CVSS metric | What it means |
|---|---|
| Attack vector (AV:L) | Local access needed |
| Attack complexity (AC:L) | Low complexity |
| Privileges required (PR:N) | No privileges required |
| User interaction (UI:N) | No user interaction |
| Scope (S:U) | Scope unchanged |
| Confidentiality (C:H) | High confidentiality impact |
| Integrity (I:H) | High integrity impact |
| Availability (A:H) | High availability impact |
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
About Mobyproject Buildkit
CVE-2026-33747 affects Mobyproject Buildkit, a product from Mobyproject. Before acting, confirm where Mobyproject Buildkit runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.
What the flaw is
In plain terms: 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 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.
The weakness class is Path Traversal. An attacker can reach files outside the intended folder by tampering with a file path.
Based on its CVSS vector, the flaw needs local or adjacent access, needs no login, and needs no user interaction. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Affected versions and timeline
| Field | Detail |
|---|---|
| Product | Mobyproject Buildkit |
| Affected versions | Buildkit before 0.28.1 |
| Published | Mar 27, 2026 |
| Last modified | Jun 17, 2026 |
| Added to CISA KEV | Not listed |
| Assigning CNA | security-advisories@github.com |
How to detect it
- Inventory every instance of Mobyproject Buildkit and record the running version against the affected range above.
- Check external attack surface scans for internet facing instances of the component.
- Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
- Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.
How to fix it
- Apply the fixed version of Mobyproject Buildkit named in the vendor advisory.
- If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
- Rescan after the change to prove the exposure is gone, then close the ticket.
CTEM action plan
| CTEM stage | What to do for this CVE |
|---|---|
| Scope | Add every business service that depends on Mobyproject Buildkit to the current CTEM cycle. |
| Discover | Find all instances, including shadow and cloud deployments, and record versions and exposure. |
| Prioritize | Rank using EPSS and CVSS together with asset exposure and business impact. |
| Validate | Confirm the flaw is reachable and exploitable in your environment and that compensating controls work. |
| Mobilize | Assign the fix to the asset owner with a due date matched to the priority, then verify closure. |
CWE References
- CWE-22: Path Traversal More CVEs with this weakness
Technical References
Frequently asked questions
Related CVEs
BuildKit custom frontends or clients using the raw low-level API can set git.checkoutbundle=true when checking out Git sources. If the Git source is malicious, this could lead to a crafted command invocation on the host.
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 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.
Mesop is a Python-based UI framework that allows users to build web applications. Versions 1.2.2 and below contain a Path Traversal vulnerability that allows any user supplying an untrusted state_token through the UI stream payload to arbitrarily target files on the disk under the standard file-based runtime backend. This can result in application denial of service (via crash loops when reading non-msgpack target files as configurations), or arbitrary file manipulation. This vulnerability heavily exposes systems hosted utilizing FileStateSessionBackend. Unauthorized malicious actors could interact with arbitrary payloads overwriting or explicitly removing underlying service resources natively outside the application bounds. This issue has been fixed in version 1.2.3.
Vociferous provides cross-platform, offline speech-to-text with local AI refinement. Prior to 4.4.2, the vulnerability exists in src/api/system.py within the export_file route. The application accepts a JSON payload containing a filename and content. While the developer intended for a native UI dialog to handle the file path, the API does not validate the filename string before it is processed by the backends filesystem logic. Because the API is unauthenticated and the CORS configuration in app.py is overly permissive (allow_origins=["*"] or allowing localhost), an external attacker can bypass the UI entirely. By using directory traversal sequences (../), an attacker can force the app to write arbitrary data to any location accessible by the current user's permissions. This vulnerability is fixed in 4.4.2.
Erugo is a self-hosted file-sharing platform. In versions up to and including 0.2.14, an authenticated low-privileged user can upload arbitrary files to any specified location due to insufficient validation of user‑supplied paths when creating shares. By specifying a writable path within the public web root, an attacker can upload and execute arbitrary code on the server, resulting in remote code execution (RCE). This vulnerability allows a low-privileged user to fully compromise the affected Erugo instance. Version 0.2.15 fixes the issue.
Arbitrary File Write via Path Traversal upload to Remote Code Execution in SeppMail User Web Interface. The affected feature is the large file transfer (LFT). This issue affects SeppMail: 15.0.2.1 and before
Earn your free CTEM certification.
Learn to scope, prioritize, validate and mobilize fixes for CVEs like CVE-2026-33747 with a free CTEM certification.
Beginner / Practitioner / Program Leader
Explore certifications