Bug 2490168 (CVE-2026-48990)

Summary:	CVE-2026-48990 joserfc: joserfc: Resource exhaustion via oversized JSON Web Signature (JWS) payloads
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	anthomas, dfreiber, drow, dschmidt, ehelms, erezende, ggainey, ilpinto, jburrell, jlanda, juwatts, kaycoth, kshier, ltomasbo, mbarnett, mhayden, mhulan, nmoumoul, osousa, pcreech, rchan, rjohnson, sdoran, simaishi, smallamp, smcdonal, stcannon, teagle, tmalecek, vkumar, yguenane, ykashtan
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in joserfc, a Python library for JSON Object Signing and Encryption (JOSE). This vulnerability allows a remote attacker to cause resource exhaustion, leading to a Denial of Service (DoS), by sending oversized JSON Web Signature (JWS) payloads. The library fails to apply size limits, specifically JWSRegistry.max_payload_length, when processing RFC7797 b64=false JWS payloads.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-06-17 22:01:14 UTC

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.