GHSA-q4xm-p75h-h9p3: Pocket ID: Client credentials grant allows any OIDC client to obtain tokens for arbitrary audiences
Pocket ID is an OIDC provider that allows users to authenticate with their passkeys to services. From 1.11.0 until 2.10.0, createTokenFromClientCredentials in backend/internal/service/oidcservice.go accepts the client-controlled resource parameter and embeds it directly in the access token aud claim without validating that the audience is registered or that the requesting client may access it. Any authenticated OIDC client can therefore obtain a Pocket ID-signed token naming another client or an arbitrary audience. The /api/oidc/introspect endpoint cannot distinguish the unauthorized token because it treats a token as active when the introspecting client's identifier matches the attacker-selected audience. In deployments where resource servers trust Pocket ID access tokens for service-to-service authorization, this bypasses audience-based access controls and can permit unauthorized data access or actions; deployments that do not use these tokens for resource-server authorization have no immediate exploitable impact. This issue is fixed in version 2.10.0.
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Pocket IDto a version that resolves this vulnerability.Fixed in 2.10.0
Event History
Frequently Asked Questions
Which deployments are actually exposed to unauthorized access?
Deployments are exposed when resource servers use Pocket ID access tokens for service-to-service authorization and rely on the token audience to enforce access controls. Deployments that do not use these tokens for resource-server authorization have no immediate exploitable impact.
What does an attacker need to exploit this issue?
The attacker needs credentials for any authenticated OIDC client. They can then request a client-credentials token with a resource parameter naming another client or an arbitrary audience.
How does the introspection endpoint contribute to exploitation?
The introspection endpoint treats a token as active when the introspecting client's identifier matches the audience selected by the attacker. It therefore cannot distinguish a token issued for an unauthorized audience from a legitimate one.
What is the affected version range and available fix?
Pocket ID versions from 1.11.0 until 2.10.0 are affected. The issue is fixed in version 2.10.0.