CVE-2025-59936 get-jwks poisoned JWKS cache allows post-fetch issuer validation bypass
Attackers can bypass JWT issuer validation by poisoning the JWKS cache, allowing forged tokens to be accepted if validation occurs after key retrieval.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-59936?
CVE-2025-59936 is a critical authentication bypass vulnerability in nearform get-jwks, published on 27 Sep 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
get-jwks contains fetch utils for JWKS keys. In versions prior to 11.0.2, a vulnerability in get-jwks can lead to cache poisoning in the JWKS key-fetching mechanism. When the iss (issuer) claim is validated only after keys are retrieved from the cache, it is possible for cached keys from an unexpected issuer to be reused, resulting in a bypass of issuer validation. This design flaw enables a potential attack where a malicious actor crafts a pair of JWTs, the first one ensuring that a chosen public key is fetched and stored in the shared JWKS cache, and the second one leveraging that cached key to pass signature validation for a targeted iss value. The vulnerability will work only if the iss validation is done after the use of get-jwks for keys retrieval. This issue has been patched in version 11.0.2.
Weakness: CWE-116
Which versions are affected by CVE-2025-59936?
2 open source packages ship an affected version, including get-jwks.
| Package | Affected | Fixed in |
|---|---|---|
get-jwks npm | All versions | 11.0.2 |
get-jwks npm | All versions | 11.0.2 |
How do I fix CVE-2025-59936?
Upgrade get-jwks to 11.0.2 or later.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2025-59936 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-59936 exists.
Sources
Also known as GHSA-qc2q-qhf3-235m.