Ory Oathkeeper has an authentication bypass by cache key confusion

Summary

ORY Oathkeeper is an Identity & Access Proxy (IAP) and Access Control Decision API that authorizes HTTP requests based on sets of Access Rules. Versions prior to 26.2.0 are vulnerable to authentication bypass due to cache key confusion. The `oauth2_introspection` authenticator cache does not distinguish tokens that were validated with different introspection URLs. An attacker can therefore legitimately use a token to prime the cache, and subsequently use the same token for rules that use a different introspection server. Ory Oathkeeper has to be configured with multiple `oauth2_introspection` authenticator servers, each accepting different tokens. The authenticators also must be configured to use caching. An attacker has to have a way to gain a valid token for one of the configured introspection servers. Starting in version 26.2.0, Ory Oathkeeper includes the introspection server URL in the cache key, preventing confusion of tokens. Update to the patched version of Ory Oathkeeper. If that is not immediately possible, disable caching for `oauth2_introspection` authenticators.

Timeline

1. Mar 26, 2026, 5:29 PM UTCCVE published
2. Mar 30, 2026, 11:19 AM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: partial

3. Mar 30, 2026, 11:20 AM UTCRecord last updated

Affected versions

• ory oathkeeper

  fixed in 26.2.0

• github.com/ory/oathkeeperGo

  fixed in 0.40.10-0.20260320084801-198a2bc82a99

References 2