CVE-2026-33496

Description

Ory Oathkeeper is 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.

Preconditions

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.

Mitigation

Ory Oathkeeper now 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.

CVE-2026-33496 has a CVSS score of 8.1 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.40.10-0.20260320084801-198a2bc82a99); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-33496? CVE-2026-33496 is a high-severity security vulnerability in github.com/ory/oathkeeper (go), affecting versions < 0.40.10-0.20260320084801-198a2bc82a99. It is fixed in 0.40.10-0.20260320084801-198a2bc82a99.
2. How severe is CVE-2026-33496? CVE-2026-33496 has a CVSS score of 8.1 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/ory/oathkeeper are affected by CVE-2026-33496? github.com/ory/oathkeeper (go) versions < 0.40.10-0.20260320084801-198a2bc82a99 is affected.
4. Is there a fix for CVE-2026-33496? Yes. CVE-2026-33496 is fixed in 0.40.10-0.20260320084801-198a2bc82a99. Upgrade to this version or later.
5. Is CVE-2026-33496 exploitable, and should I be worried? Whether CVE-2026-33496 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-33496 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-33496? Upgrade github.com/ory/oathkeeper to 0.40.10-0.20260320084801-198a2bc82a99 or later.