Vulnerability Description
joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. In versions 1.3.4 through 1.6.5, joserfc accepts oversized RFC7797 b64=false JWS payloads without applying JWSRegistry.max_payload_length, which can lead to resource exhaustion. The normal JWS compact and flattened JSON paths reject payloads above the configured payload-size limit with ExceededSizeError. The RFC7797 unencoded payload paths do not make the same check. A valid b64=false compact or flattened JSON JWS can therefore deserialize successfully with a payload larger than JWSRegistry.max_payload_length. Applications that accept lower-trust JWS values and rely on joserfc to reject oversized token content during verification have a moderate availability risk. This issue has been fixed in version 1.6.7.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/authlib/joserfc/releases/tag/1.6.7
- https://github.com/authlib/joserfc/security/advisories/GHSA-wphv-vfrh-23q5
- https://github.com/authlib/joserfc/security/advisories/GHSA-wphv-vfrh-23q5
FAQ
What is CVE-2026-48990?
CVE-2026-48990 is a vulnerability with a CVSS score of 5.3 (MEDIUM). joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. In versions 1.3.4 through 1.6.5, joserfc accepts oversized RFC7797 b64=false...
How severe is CVE-2026-48990?
CVE-2026-48990 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-48990?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.