CVE-2026-48990
joserfc: b64=false RFC7797 JWS payloads bypass JWSRegistry payload-size limits during deserialization
At a glance
- Source
- NVD
- EPSS
- EPSS 0.16 % · percentile 5 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Deferred
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.
Weaknesses (CWE)
- CWE-400 — Uncontrolled Resource Consumption
- CWE-770 — Allocation of Resources Without Limits or Throttling
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L | GitHub_M |
| CVSS 3.1 | MEDIUM 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L | NVD · security-advisories@github.com (Secondary) |
Advisories
- GHSA-wphv-vfrh-23q5 — joserfc: b64=false RFC7797 JWS payloads bypass JWSRegistry payload-size limits during deserialization
- PYSEC-2026-2530 — joserfc: b64=false RFC7797 JWS payloads bypass JWSRegistry payload-size limits during deserialization
European references
- ENISA EUVD · EUVD-2026-37805
- GCVE · GCVE-0-2026-48990
CERT-FR advisories
- CERTFR-2026-AVI-0933 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
Affected products
| Product | Versions |
|---|---|
| authlib · joserfc | affected < 1.6.7 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |