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CVE-2026-55603

Estado: AnalizadaAlta (7.5)—

http-proxy-middleware is node.js http-proxy middleware. From 3.0.4 until 3.0.7 and 4.1.1, fixRequestBody() is the library's documented helper for re-emitting a request body that was already consumed by a body parser. When the outgoing Content-Type is multipart/form-data, it rebuilds the body with handlerFormDataBodyData(), which interpolates each req.body key and value directly into the multipart wire format without neutralizing CR/LF. A \r\n inside a value (or key) lets an attacker close the current part and inject an entirely new form part.

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Because the proxy's own body parser saw a single opaque value, any gateway-side policy or validation performed on req.body is evaluated against a different set of fields than the upstream backend ultimately parses a request/parameter desynchronization across the trust boundary. This vulnerability is fixed in 3.0.7 and 4.1.1.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

CVSS AV:N/AC:H sin UI:R indica explotación remota (T1190). El ataque manipula datos multipart inyectando CR/LF para desincronizar parsing (T1565.002: manipulación de datos en tránsito). Actúa como proxy entre validación y backend, permitiendo bypass de políticas (T1090.001: SSRF implícito en desincr

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Vulnerability ScanningPrivileged Account ManagementNetwork SegmentationNetwork Intrusion PreventionLimit Access to Resource Over NetworkFilter Network Traffic

Tecnologías afectadas (1)

Chimurai — Http-proxy-middleware

CWE

Referencias

JSON original (NVD)

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  "lastModified": "2026-06-24T16:44:28.870",
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