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OpenAdvisories
Medium · 5.3 CVE-2026-48990 EUVD-2026-37805GHSA-wphv-vfrh-23q5PYSEC-2026-2530

joserfc: b64=false RFC7797 JWS payloads bypass JWSRegistry payload-size limits during deserialization

Published Jun 17, 2026 · Updated Jun 18, 2026 · Assigned by GitHub_M

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.

Affected products

VendorProductAffectedFixed
authlib joserfc < 1.6.7 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 joserfc 1.6.8-1 —
Debian 13 joserfc No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.04 LTS joserfc No fix yet —
Ubuntu 25.10 joserfc No fix yet —
ReleasePackageFixed inAdvisory
Red Hat Hardened Images 1 jaeger 2.19.0-1.hum1 RHSA-2026:25039
ReleasePackageFixed inAdvisory
openSUSE Tumbleweed python-joserfc 1.7.1-1.1 openSUSE-SU-2026:11067-1

Wolfi

ReleasePackageFixed inAdvisory
Wolfi rolling airflow-3 3.2.2-r9 —

Affected packages

EcosystemPackageAffectedFixedRecord
PyPI joserfc >= 1.3.4, < 1.6.7 1.6.7 GHSA-wphv-vfrh-23q5

Advisories 2

References