CVE-2026-33748
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedBuildKit 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceBuildKit fails to properly validate the subdir component in Git URLs, allowing path traversal through symlinks to access files outside the checked-out repository root on the same mounted filesystem. This vulnerability is triggered when building Dockerfiles that reference Git URLs containing a subpath component, potentially exposing sensitive files to malicious build contexts.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 0.28.1CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify your BuildKit versionRun `buildctl --version` or check the version of the `moby-buildkit` package installed in your system (e.g., `docker info | grep -i buildkit` or your package manager)Affected if The installed version is lower than 0.28.1 (e.g., 0.27.x, 0.26.x, etc.)
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Locate Dockerfiles that use Git URLsSearch your project files for Dockerfile patterns referencing Git repositories, such as `FROM git://...`, `FROM https://...github.com/...`, `git clone` commands in build scripts, or any Dockerfile instruction that pulls from a Git URLAffected if You have Dockerfiles or build scripts that reference remote Git repositories as the source for builds
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Check if Git URLs include a subdirectory pathExamine any Git URL references found in the previous step for a subpath component (typically after a `#` fragment or as part of the URL path, like `github.com/user/repo/path/to/subdir`)Affected if Any of the Git URLs contain a subdirectory or subpath component pointing to a specific location within the repository
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Inspect the build context for symlinksIf you use Git URLs with subpaths, review the repositories involved to determine if any files or directories in the subpath resolve to symbolic links that could point outside the repository rootAffected if The subpath resolves to or contains symlinks that point to locations outside the checked-out repository directory
You are affected if your BuildKit version is below 0.28.1 AND you build Dockerfiles using Git URLs that include a subdirectory component, where that subpath could resolve to a symlink outside the repository root.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped0.28.1
Upgrade BuildKit to version 0.28.1 or later. As a temporary workaround, avoid building Dockerfiles from untrusted sources and refrain from using the subdir component with untrusted Git repositories where the subpath could point to a symlink.
Buildkit v0.28.1
- Upgrade Buildkit to version 0.28.1 or later
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation3.0 h
- Testing4.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-33748 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-33748 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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