CVE-2026-34240 (GCVE-0-2026-34240)

Vulnerability from cvelistv5 – Published: 2026-03-31 15:44 – Updated: 2026-04-01 14:03
VLAI
Title
jose vulnerable to untrusted JWK header key acceptance during signature verification
Summary
JOSE is a Javascript Object Signing and Encryption (JOSE) library. Prior to version 0.3.5+1, a vulnerability in jose could allow an unauthenticated, remote attacker to forge valid JWS/JWT tokens by using a key embedded in the JOSE header (jwk). The vulnerability exists because key selection could treat header-provided jwk as a verification candidate even when that key was not present in the trusted key store. Since JOSE headers are untrusted input, an attacker could exploit this by creating a token payload, embedding an attacker-controlled public key in the header, and signing with the matching private key. Applications using affected versions for token verification are impacted. This issue has been patched in version 0.3.5+1. A workaround for this issue involves rejecting tokens where header jwk is present unless that jwk matches a key already present in the application's trusted key store.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-04-01 14:02 UTC
CWE
  • CWE-347 - Improper Verification of Cryptographic Signature
Assigner
GitHub_M CNA
References
Impacted products
Vendor Product Version
appsup-dart jose Affected: < 0.3.5+1
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