GHSA-c7xh-gjv4-4jgv is a medium-severity (CVSS 6.4) vulnerability in github.com/kcp-dev/kcp. A fix is available for github.com/kcp-dev/kcp — see the affected versions and patch details below.
kcp's impersonation allows access to global administrative groups
Real-World Exposure
github.com/kcp-dev/kcpReal-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
Impersonation is a feature of the Kubernetes API, allowing to override user information. As downstream project, kcp inherits this feature. As per the linked documentation a specific level of privilege (usually assigned to cluster admins) is required for impersonation.
The vulnerability in kcp affects kcp installations in which users are granted the cluster-admin ClusterRole (or comparably high permission levels that grant impersonation access; the verb in question is impersonate) within their respective workspaces. As kcp builds around self-service confined within workspaces, most installations would likely grant such workspace access to their users. Such users can impersonate special global administrative groups, which circumvent parts of the authorizer chains, e.g. maximal permission policies.
Patches
The problem has been patched in #3206 and is available in kcp 0.26.1 and higher.
Workarounds
- Not assigning the
cluster-adminrole (or any other role granting blanket impersonation permissions) to users. - A reverse proxy between users and kcp to check for the
Impersonate-Groupheader and reject requests that impersonate global administrative groups.
References
See the pull request (#3206).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/kcp-dev/kcp | all versions | 0.26.1go get github.com/kcp-dev/kcp@v0.26.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/kcp-dev/kcp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/kcp-dev/kcp to 0.26.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-c7xh-gjv4-4jgv 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-c7xh-gjv4-4jgv can be triaged on real exposure rather than presence alone.
Tailored to GHSA-c7xh-gjv4-4jgv. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-c7xh-gjv4-4jgv in your dependencies?
O3 Security finds GHSA-c7xh-gjv4-4jgv across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.