CVE-2026-30827

{"id": "CVE-2026-30827", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}]}, "published": "2026-03-07T06:16:10.507", "references": [{"url": "https://github.com/express-rate-limit/express-rate-limit/commit/14e53888cdfd1b9798faf5b634c4206409e27fc4", "tags": ["Patch"], "source": "security-advisories@github.com"}, {"url": "https://github.com/express-rate-limit/express-rate-limit/security/advisories/GHSA-46wh-pxpv-q5gq", "tags": ["Exploit", "Patch", "Vendor Advisory"], "source": "security-advisories@github.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-770"}]}], "descriptions": [{"lang": "en", "value": "express-rate-limit is a basic rate-limiting middleware for Express. In versions starting from 8.0.0 and prior to versions 8.0.2, 8.1.1, 8.2.2, and 8.3.0, the default keyGenerator in express-rate-limit applies IPv6 subnet masking (/56 by default) to all addresses that net.isIPv6() returns true for. This includes IPv4-mapped IPv6 addresses (::ffff:x.x.x.x), which Node.js returns as request.ip on dual-stack servers. Because the first 80 bits of all IPv4-mapped addresses are zero, a /56 (or any /32 to /80) subnet mask produces the same network key (::/56) for every IPv4 client. This collapses all IPv4 traffic into a single rate-limit bucket: one client exhausting the limit causes HTTP 429 for all other IPv4 clients. This issue has been patched in versions 8.0.2, 8.1.1, 8.2.2, and 8.3.0."}, {"lang": "es", "value": "express-rate-limit es un middleware b\u00e1sico de limitaci\u00f3n de tasa para Express. En versiones a partir de la 8.0.0 y anteriores a las versiones 8.0.2, 8.1.1, 8.2.2 y 8.3.0, el keyGenerator predeterminado en express-rate-limit aplica enmascaramiento de subred IPv6 (/56 por defecto) a todas las direcciones para las que net.isIPv6() devuelve verdadero. Esto incluye direcciones IPv6 mapeadas a IPv4 (::ffff:x.x.x.x), que Node.js devuelve como request.ip en servidores de doble pila. Debido a que los primeros 80 bits de todas las direcciones mapeadas a IPv4 son cero, una m\u00e1scara de subred /56 (o cualquier /32 a /80) produce la misma clave de red (::/56) para cada cliente IPv4. Esto colapsa todo el tr\u00e1fico IPv4 en un \u00fanico cubo de limitaci\u00f3n de tasa: un cliente que agota el l\u00edmite causa HTTP 429 para todos los dem\u00e1s clientes IPv4. Este problema ha sido parcheado en las versiones 8.0.2, 8.1.1, 8.2.2 y 8.3.0."}], "lastModified": "2026-03-11T19:00:50.690", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:express-rate-limit_project:express-rate-limit:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "AE5ED6AB-D445-4E61-86B1-FBC0659382A0", "versionEndExcluding": "8.0.2", "versionStartIncluding": "8.0.0"}, {"criteria": "cpe:2.3:a:express-rate-limit_project:express-rate-limit:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "F501D9EB-DFE4-496D-8471-61DE755B9E05", "versionEndExcluding": "8.2.2", "versionStartIncluding": "8.2.0"}, {"criteria": "cpe:2.3:a:express-rate-limit_project:express-rate-limit:8.1.0:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "C56713D6-533F-424A-B511-5E63014709D8"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}