Resource Exhaustion Vulnerability in joserfc Python Library
CVE-2026-48990

5.3MEDIUM

Key Information:

Vendor

Authlib

Status
Joserfc
Vendor
CVE Published:
17 June 2026

What is CVE-2026-48990?

The joserfc Python library, which implements various JSON Object Signing and Encryption (JOSE) standards, has a vulnerability in its handling of oversized payloads. In versions 1.3.4 to 1.6.5, the library fails to enforce maximum payload size limits when processing unencoded payloads, potentially allowing malicious actors to cause resource exhaustion. Normally, the library correctly rejects oversized compact and flattened JSON paths, raising an ExceededSizeError, but this validation is not applied to certain payload paths. As a result, applications depending on joserfc for secure verification of lower-trust JWS values may face moderate availability risks. The issue has been addressed in version 1.6.7.

Affected Version(s)

joserfc < 1.6.7

References

https://github.com/authlib/joserfc/security/advisories/GH...
x_refsource_CONFIRM
https://github.com/authlib/joserfc/releases/tag/1.6.7
x_refsource_MISC

CVSS V3.1

Score:
5.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.