🛡️ GHSA-c7xh-gjv4-4jgv — kcp

⚪ Unknown ✅ No Known Exploit CWE-285 OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

kcp's impersonation allows access to global administrative groups

Impact

[Impersonation](https://kubernetes.io/docs/reference/access-authn-authz/authentication/#user-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](https://docs.kcp.io/kcp/v0.26/concepts/apis/exporting-apis/#maximal-permission-policy).

Patches

The problem has been patched in #3206 and is available in kcp 0.26.1 and higher.

Workarounds

  • Not assigning the cluster-admin role (or any other role granting blanket impersonation permissions) to users.
  • A reverse proxy between users and kcp to check for the Impersonate-Group header and reject requests that impersonate global administrative groups.

References

See the pull request (#3206).

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality low, integrity low, availability none.

Weakness class

GHSA-c7xh-gjv4-4jgv is classified as CWE-285: Improper Authorization. A request is carried out without confirming that the caller is permitted to perform it on that specific resource.

Affected software

GHSA-c7xh-gjv4-4jgv is recorded against 1 package.

  • github.com/kcp-dev/kcp

Timeline and source

Published on 11 December 2024 and last revised on 12 December 2024. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

github.com (Web)
github.com (Web)
github.com (Web)
github.com (Package)
pkg.go.dev (Web)

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
CWE CWE-285
Public Exploit ✅ No
Source OSV
Published 2024-12-11
Updated 2026-08-20
Modified 2024-12-12
Fix URL N/A

Affected Packages

Software From version Fixed in
github.com/kcp-dev/kcp — —

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