CVE-2026-33495 Ory Oathkeeper has an authentication bypass by usage of untrusted header

What is CVE-2026-33495?

CVE-2026-33495 is a medium-severity authentication bypass vulnerability in ory oathkeeper, published on 26 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

ORY Oathkeeper is an Identity & Access Proxy (IAP) and Access Control Decision API that authorizes HTTP requests based on sets of Access Rules. Ory Oathkeeper is often deployed behind other components like CDNs, WAFs, or reverse proxies. Depending on the setup, another component might forward the request to the Oathkeeper proxy with a different protocol (http vs. https) than the original request. In order to properly match the request against the configured rules, Oathkeeper considers the `X-Forwarded-Proto` header when evaluating rules. The configuration option `serve.proxy.trust_forwarded_headers` (defaults to false) governs whether this and other `X-Forwarded-*` headers should be trusted. Prior to version 26.2.0, Oathkeeper did not properly respect this configuration, and would always consider the `X-Forwarded-Proto` header. In order for an attacker to abuse this, an installation of Ory Oathkeeper needs to have distinct rules for HTTP and HTTPS requests. Also, the attacker needs to be able to trigger one but not the other rule. In this scenario, the attacker can send the same request but with the `X-Forwarded-Proto` header in order to trigger the other rule. We do not expect many configurations to meet these preconditions. Version 26.2.0 contains a patch. Ory Oathkeeper will correctly respect the `serve.proxy.trust_forwarded_headers` configuration going forward, thereby eliminating the attack scenario. We recommend upgrading to a fixed version even if the preconditions are not met. As an additional mitigation, it is generally recommended to drop any unexpected headers as early as possible when a request is handled, e.g. in the WAF.

Weakness: CWE-862

Which versions are affected by CVE-2026-33495?

3 open source packages ship an affected version, including github.com/ory/oathkeeper. It affects 1 product.

Products include Ory Oathkeeper.

How do I fix CVE-2026-33495?

Upgrade github.com/ory/oathkeeper to 0.40.10-0.20260320084810-e9acca14a04d or later.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2026-33495 being exploited?

There is no known exploitation of CVE-2026-33495 in the wild and no public exploit code.

Other vulnerabilities in ory oathkeeper

• CVE-2026-33494 Ory Oathkeeper has a path traversal authorization bypass Critical 10.0
• CVE-2026-33496 Ory Oathkeeper has an authentication bypass by cache key confusion High 8.1
• CVE-2021-32701 Possible bypass of token claim validation when OAuth2 Introspection caching is enabled High 7.5

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-vhr5-ggp3-qq85, GO-2026-4810.