GHSA-vhr5-ggp3-qq85 · Severity: medium · Ecosystem: go — Ory Oathkeeper has an authentication bypass by usage of untrusted header
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.
Conclusion & alert: CVE-2026-33495 is rated Low Risk (28.6/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.03%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-03-27 | — | 0.03% | — |
Full EPSS history (1 record total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 6.5 | 3.1 | MEDIUM |
|
3.9 | 2.5 | [email protected] |
GHSA-vhr5-ggp3-qq85 · Severity: medium · Ecosystem: go — Ory Oathkeeper has an authentication bypass by usage of untrusted header
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| ory | oathkeeper | < 26.2.0 | cpe:2.3:a:ory:oathkeeper:*:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| https://github.com/ory/oathkeeper/commit/e9acca14a04d246250557550065e4b4576525bd5 | Patch |
| https://github.com/ory/oathkeeper/security/advisories/GHSA-vhr5-ggp3-qq85 | Mitigation Vendor Advisory |