CVE-2026-119284: medium-severity vulnerability in authlib joserfc
joserfc: Compact JWS size guard allocates attacker-controlled segments before rejection
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 6.9epss 0.2%
joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to 1.7.6, joserfc compact JWS deserialization calls bytes.split() before enforcing the existing aggregate segment-size limits. When attacker-controlled compact serialization bytes reach deserialize_compact(), the split creates copies of the header, payload, and signature segments before ExceededSizeError rejects them, causing an additional allocation approximately proportional to the supplied token. Requests that exhaust available process memory can therefore cause an availability failure even though signature verification fails. This issue is fixed in version 1.7.6.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Affected products
authlib · joserfcRelated CVEs — authlib joserfc
In the same product, most dangerous first.
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-2026-49852HIGHjoserfc: HS256/HS384/HS512 verify accepts empty/nil HMAC key (cross-language sibling of CVE-2026-45363)EPSS 0.2%CVE-2026-62995LOWjoserfc accepts JWT with padding, leading to JWT malleabilityEPSS 0.1%