GHSA-mc8v-mgrf-8f4m is a low-severity (CVSS 3) CWE-843 vulnerability in github.com/opencontainers/distribution-spec. O3 Security confirms whether GHSA-mc8v-mgrf-8f4m is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Clarify Content-Type handling
Real-World Exposure
github.com/opencontainers/distribution-specReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Impact
In the OCI Distribution Specification version 1.0.0 and prior, the Content-Type header alone was used to determine the type of document during push and pull operations. Documents that contain both “manifests” and “layers” fields could be interpreted as either a manifest or an index in the absence of an accompanying Content-Type header. If a Content-Type header changed between two pulls of the same digest, a client may interpret the resulting content differently.
Patches
The OCI Distribution Specification will be updated to require that a mediaType value present in a manifest or index match the Content-Type header used during the push and pull operations.
Workarounds
Clients pulling from a registry may distrust the Content-Type header and reject an ambiguous document that contains both “manifests” and “layers” fields or “manifests” and “config” fields.
References
https://github.com/opencontainers/image-spec/security/advisories/GHSA-77vh-xpmg-72qh
For more information
If you have any questions or comments about this advisory:
- Open an issue in https://github.com/opencontainers/distribution-spec/
- Email us at [email protected]
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/opencontainers/distribution-spec | all versions | 1.0.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/opencontainers/distribution-spec. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/opencontainers/distribution-spec to 1.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mc8v-mgrf-8f4m is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-mc8v-mgrf-8f4m is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-mc8v-mgrf-8f4m. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
As a consequence of the OCI Image Specification (and OCI Distribution Specification [1]), container runtime engines (like containerd, moby - Docker Engine, cri-o) deliver updates to adopt new `mediaType` field used for identification of the document type. Even though some Red Hat products rely on container engine, the…
Frequently Asked Questions
Is GHSA-mc8v-mgrf-8f4m in your dependencies?
O3 detects GHSA-mc8v-mgrf-8f4m across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.