GHSA-q6hv-wcjr-wp8h Impact Because UPDATE validation is not being applied, it is possible for an actor with access to an instance of the [initializingworksp

Not scored Published 26 Sep 2025

Attackers with virtual workspace access can bypass LogicalCluster initialization checks, potentially skipping security or billing integrations.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is GHSA-q6hv-wcjr-wp8h?

GHSA-q6hv-wcjr-wp8h is a missing authorization vulnerability in github.com/kcp-dev/kcp, published on 26 Sep 2025. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Impact

Because UPDATE validation is not being applied, it is possible for an actor with access to an instance of the initializingworkspaces virtual workspace to run arbitrary patches on the status field of LogicalCluster objects while the workspace is initializing.

This allows to add or remove any initializers as well as changing the phase of a LogicalCluster (to "Ready" for example).

As this effectively allows to skip certain initializers or the entire initialization phase, potential integrations with external systems such as billing or security could be affected. Their initializers could be skipped by a WorkspaceType that adds another initializer and grants permissions to the virtual workspace to a rogue or compromised entity.

Who is impacted?

Impacts other owners of WorkspaceTypes with initializers that are inherited by other WorkspaceTypes.
Impacts developers using the virtual/framework package to create their own virtualworkspaces if they are using UpdateFuncs in their custom storageWrappers.

Details

The issue occurs because the rest.ValidateObjectUpdateFunc is not being called within the DefaultDynamicDelegatedStoreFuncs. As a result, the intended status overwrite protection from initializers never gets called, allowing arbitrary logicalcluster status patches.

Patches

The problem has been patched in #3599 and is available in kcp 0.28.3 and higher.

Workarounds

Further limit access to the initialize verb on WorkspaceType objects (see documentation for details).
Only use trusted WorkspaceType objects.

References

See the pull request (#3599).

Which versions are affected by GHSA-q6hv-wcjr-wp8h?

3 open source packages ship an affected version, including github.com/kcp-dev/kcp.

Package	Affected	Fixed in
`github.com/kcp-dev/kcp` Go	All versions	`0.28.3`
`github.com/kcp-dev/kcp` Go	All versions	`0.28.3`
`github.com/kcp-dev/kcp` Go	All versions	`0.28.3`

How do I fix GHSA-q6hv-wcjr-wp8h?

Upgrade github.com/kcp-dev/kcp to 0.28.3 or later.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is GHSA-q6hv-wcjr-wp8h being exploited?

There is no known exploitation of GHSA-q6hv-wcjr-wp8h in the wild and no public exploit code.

Sources

Also known as GO-2025-3985.