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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.

PUBLISHED Reserved 2026-05-26 | Published 2026-06-17 | Updated 2026-06-18 | Assigner GitHub_M




MEDIUM: 5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Problem types

CWE-400: Uncontrolled Resource Consumption

CWE-770: Allocation of Resources Without Limits or Throttling

Product status

< 1.6.7
affected

References

github.com/...oserfc/security/advisories/GHSA-wphv-vfrh-23q5 exploit

github.com/...oserfc/security/advisories/GHSA-wphv-vfrh-23q5

github.com/authlib/joserfc/releases/tag/1.6.7

cve.org (CVE-2026-48990)

nvd.nist.gov (CVE-2026-48990)

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