CVE-2025-30144

{"id": "CVE-2025-30144", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 6.5, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "LOW"}, "impactScore": 4.2, "exploitabilityScore": 2.2}]}, "published": "2025-03-19T16:15:33.080", "references": [{"url": "https://datatracker.ietf.org/doc/html/rfc7519#page-9", "source": "security-advisories@github.com"}, {"url": "https://github.com/nearform/fast-jwt/commit/cc26b1d473f900446ad846f8f0b10eb1c0adcbdd", "source": "security-advisories@github.com"}, {"url": "https://github.com/nearform/fast-jwt/security/advisories/GHSA-gm45-q3v2-6cf8", "source": "security-advisories@github.com"}], "vulnStatus": "Deferred", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-290"}, {"lang": "en", "value": "CWE-345"}]}], "descriptions": [{"lang": "en", "value": "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."}, {"lang": "es", "value": "fast-jwt proporciona una implementaci\u00f3n r\u00e1pida de JSON Web Token (JWT). Antes de la versi\u00f3n 5.0.6, la librer\u00eda fast-jwt no validaba correctamente la declaraci\u00f3n iss seg\u00fan el RFC 7519. La validaci\u00f3n de la declaraci\u00f3n iss (emisor) dentro de la librer\u00eda fast-jwt permite una matriz de cadenas como valor iss v\u00e1lido. Esta falla de dise\u00f1o permite un posible ataque donde un actor malicioso manipula un JWT con una declaraci\u00f3n iss estructurada como ['https://attacker-domain/', 'https://valid-iss']. Debido a la validaci\u00f3n permisiva, el JWT se considerar\u00e1 v\u00e1lido. Adem\u00e1s, si la aplicaci\u00f3n utiliza librer\u00edas externas como get-jwks, que no validan de forma independiente la declaraci\u00f3n iss, el atacante puede aprovechar esta vulnerabilidad para falsificar un JWT que sea aceptado por la aplicaci\u00f3n v\u00edctima. En esencia, el atacante puede insertar su propio dominio en la matriz iss, junto con el emisor leg\u00edtimo, y eludir las comprobaciones de seguridad previstas. Este problema se solucion\u00f3 en la versi\u00f3n 5.0.6."}], "lastModified": "2026-04-15T00:35:42.020", "sourceIdentifier": "security-advisories@github.com"}