Ory Oathkeeper has an authentication bypass by cache key confusion

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.1 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

EPSS

• CVE-2026-33496: 0.38% estimated exploitation activity in the next 30 days; percentile 32.56 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Description Ory Oathkeeper is vulnerable to authentication bypass due to cache key confusion. The oauth2introspection 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 oauth2introspection 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 oauth2introspection authenticators.

Published by the source

20 Mar 2026, 20:51 UTC

Last modified by the source

27 Mar 2026, 20:59 UTC

Source last checked

26 Oct 2026, 15:18 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-4mq7-pvjg-xp2r

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# Patch Next advisory brief: CVE-2026-33496

Advisory: Ory Oathkeeper has an authentication bypass by cache key confusion
IDs: CVE-2026-33496, GHSA-4mq7-pvjg-xp2r
Record: https://patchnext.com/advisories/cve-2026-33496 (revision 1, source checked 26 Oct 2026, 15:18 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/ory/oathkeeper 0.40.10-0.20260320084801-198a2bc82a99. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/ory/oathkeeper: affected < 0.40.10-0.20260320084801-198a2bc82a99; fixed in 0.40.10-0.20260320084801-198a2bc82a99

## Suggested inspection (read-only)
- Go github.com/ory/oathkeeper: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/ory/oathkeeper.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-4mq7-pvjg-xp2r (GitHub-reviewed advisory GHSA-4mq7-pvjg-xp2r lists affected ranges: Go github.com/ory/oathkeeper >=0 <0.40.10-0.20260320084801-198a2bc82a99)

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