CVE-ID

CVE-2025-30144

• CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
fast-jwt provides fast JSON Web Token (JWT) implementation. Prior to 5.0.6, the fast-jwt library does not properly validate the iss claim based on the RFC 7519. The iss (issuer) claim validation within the fast-jwt library permits an array of strings as a valid iss value. This design flaw enables a potential attack where a malicious actor crafts a JWT with an iss claim structured as ['https://attacker-domain/', 'https://valid-iss']. Due to the permissive validation, the JWT will be deemed valid. Furthermore, if the application relies on external libraries like get-jwks that do not independently validate the iss claim, the attacker can leverage this vulnerability to forge a JWT that will be accepted by the victim application. Essentially, the attacker can insert their own domain into the iss array, alongside the legitimate issuer, and bypass the intended security checks. This issue is fixed in 5.0.6.
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
Assigning CNA
GitHub (maintainer security advisories)
Date Record Created
20250317 Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20250317)
Votes (Legacy)
Comments (Legacy)
Proposed (Legacy)
N/A
This is an record on the CVE List, which provides common identifiers for publicly known cybersecurity vulnerabilities.