CVE-2025-27370 Auth bypass in OpenID Connect
A malicious Authorization Server can impersonate a Client by injecting attacker-controlled audience values when private_key_jwt authentication is used.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2025-27370?
CVE-2025-27370 is a medium-severity authentication bypass vulnerability in OpenID Connect, published on 3 Mar 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
OpenID Connect Core through 1.0 errata set 2 allows audience injection in certain situations. When the private_key_jwt authentication mechanism is used, a malicious Authorization Server could trick a Client into writing attacker-controlled values into the audience, including token endpoints or issuer identifiers of other Authorization Servers. The malicious Authorization Server could then use these private key JWTs to impersonate the Client.
Weakness: CWE-305
Which versions are affected by CVE-2025-27370?
How do I fix CVE-2025-27370?
No fix has been published for CVE-2025-27370 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2025-27370 being exploited?
There is no known exploitation of CVE-2025-27370 in the wild and no public exploit code.
Sources
Also known as GHSA-pcj4-9fcj-56c8.