Is CVE-2026-48990 actively exploited?

No active exploitation of CVE-2026-48990 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-48990 be exploited remotely?

Yes. CVE-2026-48990 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-48990?

CVE-2026-48990 has a CVSS score of 5.3 (MEDIUM).

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MEDIUM

CVE-2026-48990

CWE-400Published: June 17, 2026· Updated: Jun 23, 2026

5.3

CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2026-48990 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.