CVE-2026-49852: falha de alta gravidade em authlib joserfc
joserfc: HS256/HS384/HS512 verify accepts empty/nil HMAC key (cross-language sibling of CVE-2026-45363)
Publicada em · Atualizada em
Aviso por e-mail quando ela entrar no KEV, ganhar PoC pública ou subir de nota.
21Vexday Risk Score
Sem sinal de exploração. Nenhum artefato público de exploração conhecido até agora.
ssvc Trackcvss 8.7epss 0.2%
joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to 1.6.8, joserfc.jwt.decode accepts attacker-forged HMAC-signed tokens when the caller-supplied verification key is the empty string or None, because HMACAlgorithm.sign and HMACAlgorithm.verify in src/joserfc/_rfc7518/jws_algs.py pass the output of OctKey.get_op_key(...) to hmac.new(...) and OctKey.import_key in src/joserfc/_rfc7518/oct_key.py only emits a SecurityWarning for keys shorter than 14 bytes without rejecting zero-length input. This issue is fixed in version 1.6.8.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Produtos afetados
authlib · joserfcCVEs relacionadas — authlib joserfc
No mesmo produto, das mais perigosas para as menos.
CVE-2026-27932HIGHjoserfc PBES2 p2c Unbounded Iteration Count enables Denial of Service (DoS)EPSS 0.5%CVE-2025-65015CRITICALjoserfc has Possible Uncontrolled Resource Consumption Vulnerability Triggered by Logging Arbitrarily Large JWT Token PayloadsEPSS 0.4%CVE-2026-48990MEDIUMjoserfc: b64=false RFC7797 JWS payloads bypass JWSRegistry payload-size limits during deserializationEPSS 0.2%CVE-2026-119283HIGHjoserfc: Unbounded JWE General JSON `recipients` Array Leads to CPU Exhaustion (DoS) via Repeated RSA Private-Key DecryptionEPSS 0.2%CVE-2026-119284MEDIUMjoserfc: Compact JWS size guard allocates attacker-controlled segments before rejectionEPSS 0.2%CVE-2026-62995LOWjoserfc accepts JWT with padding, leading to JWT malleabilityEPSS 0.1%