CVE-2021-32701 Possible bypass of token claim validation when OAuth2 Introspection caching is enabled

What is CVE-2021-32701?

CVE-2021-32701 is a high-severity authentication bypass vulnerability in ory oathkeeper, published on 22 Jun 2021. 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. When you make a request to an endpoint that requires the scope `foo` using an access token granted with that `foo` scope, introspection will be valid and that token will be cached. The problem comes when a second requests to an endpoint that requires the scope `bar` is made before the cache has expired. Whether the token is granted or not to the `bar` scope, introspection will be valid. A patch will be released with `v0.38.12-beta.1`. Per default, caching is disabled for the `oauth2_introspection` authenticator. When caching is disabled, this vulnerability does not exist. The cache is checked in [`func (a *AuthenticatorOAuth2Introspection) Authenticate(...)`](https://github.com/ory/oathkeeper/blob/6a31df1c3779425e05db1c2a381166b087cb29a4/pipeline/authn/authenticator_oauth2_introspection.go#L152). From [`tokenFromCache()`](https://github.com/ory/oathkeeper/blob/6a31df1c3779425e05db1c2a381166b087cb29a4/pipeline/authn/authenticator_oauth2_introspection.go#L97) it seems that it only validates the token expiration date, but ignores whether the token has or not the proper scopes. The vulnerability was introduced in PR #424. During review, we failed to require appropriate test coverage by the submitter which is the primary reason that the vulnerability passed the review process.

Weakness: CWE-863

Which versions are affected by CVE-2021-32701?

6 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-2021-32701?

Upgrade github.com/ory/oathkeeper to 0.38.12-beta.1 or later.

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

Is CVE-2021-32701 being exploited?

There is no known exploitation of CVE-2021-32701 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-2026-33495 Ory Oathkeeper has an authentication bypass by usage of untrusted header Medium 6.5

Sources

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

Also known as GHSA-qvp4-rpmr-xwrr, GHSA-vfvf-6gx5-mqv6, GO-2022-0406, GO-2022-0920.