VulnerabilityDeferred

CVE-2025-59936

In versions prior to 11.0.2, a vulnerability in get-jwks can lead to cache poisoning in the JWKS key-fetching mechanism.

CRITICAL 9.4EPSS 0.40%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.40%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 3.0: 9.4 CRITICALCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
EPSS: 0.40% probability · 34th percentile
CISA KEV: Not listed
Weakness: CWE-116
Source: security-advisories@github.com

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.