GHSA-w2rr-38wv-8rrp is a critical-severity (CVSS 9.6) CWE-285 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 allows unauthorized creation and deletion of objects in arbitrary workspaces through APIExport Virtual Workspace
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-w2rr-38wv-8rrp.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-w2rr-38wv-8rrp plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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
The APIExport Virtual Workspace can be used to manage objects in workspaces that bind that APIExport for resources defined in the APIExport or specified and accepted via permission claims. This allows an API provider (via their APIExport) scoped down access to workspaces of API consumers to provide their services properly.
The identified vulnerability allows creating or deleting an object via the APIExport VirtualWorkspace in any arbitrary target workspace for pre-existing resources. By design, this should only be allowed when the workspace owner decides to give access to an API provider by creating an APIBinding.
With this vulnerability, it is possible for an attacker to create and delete objects even if none of these requirements are satisfied, i.e. even if there is no APIBinding in that workspace at all or the workspace owner has created an APIBinding, but rejected a permission claim.
Patches
A fix for this issue has been identified and has been published with kcp 0.26.3 and 0.27.0.
Workarounds
For users unable to upgrade to one of the patched versions, the following guidance can be given:
- Minimise the set of people with
apiexport/contentsub-resource access toAPIExportresources. Be aware that this has to apply to all workspaces to be effective. - Filter incoming requests in a reverse proxy with a similar logic as the authorizer added in the referenced pull request.
References
See pull request (https://github.com/kcp-dev/kcp/pull/3338).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/kcp-dev/kcp | all versions | 0.26.3go get github.com/kcp-dev/kcp@v0.26.3 |
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 0.26.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-w2rr-38wv-8rrp 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-w2rr-38wv-8rrp can be triaged on real exposure rather than presence alone.
Tailored to GHSA-w2rr-38wv-8rrp. 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-w2rr-38wv-8rrp in your dependencies?
O3 Security finds GHSA-w2rr-38wv-8rrp across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.