CVE-2026-48990
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.
- Score
- CVSS 3.1 5.3 Medium
- Status
- Deferred - security-advisories@github.com
- Published
- 2026-06-17
- Last modified
- 2026-10-26
- Weaknesses
- CWE-400, CWE-770
Affected products
References
- https://github.com/authlib/joserfc/security/advisories/GHSA-wphv-vfrh-23q5
- https://github.com/authlib/joserfc/releases/tag/1.6.7
