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CVE-2026-2833

Estado: AnalizadaCrítica (9.3)—

An HTTP request smuggling vulnerability (CWE-444) was found in Pingora's handling of HTTP/1.1 connection upgrades. The issue occurs when a Pingora proxy reads a request containing an Upgrade header, causing the proxy to pass through the rest of the bytes on the connection to a backend before the backend has accepted the upgrade. An attacker can thus directly forward a malicious payload after a request with an Upgrade header to that backend in a way that may be interpreted as a subsequent request header, bypassing proxy-level security controls and enabling cross-user session hijacking.

Impact

This vulnerability primarily affects standalone Pingora deployments where a Pingora proxy is exposed to external traffic. An attacker could exploit this to:

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Cloudflare's CDN infrastructure was not affected by this vulnerability, as ingress proxies in the CDN stack maintain proper HTTP parsing boundaries and do not prematurely switch to upgraded connection forwarding mode.

Mitigation:

Pingora users should upgrade to Pingora v0.8.0 or higher

As a workaround, users may return an error on requests with the Upgrade header present in their request filter logic in order to stop processing bytes beyond the request header and disable downstream connection reuse.

Detalles técnicos trazas, registros y código del informe original
  *  Bypass proxy-level ACL controls and WAF logic

  *  Poison caches and upstream connections, causing subsequent requests from legitimate users to receive responses intended for smuggled requests

  *  Perform cross-user attacks by hijacking sessions or smuggling requests that appear to originate from the trusted proxy IP

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.

HTTP request smuggling en proxy expuesto a tráfico externo (AV:N, PR:N, UI:N) exfiltración de datos y secuestro de sesiones mediante bypass de controles WAF y envenenamiento de caché.

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

Privileged Account ManagementNetwork SegmentationFilter Network TrafficApplication Developer GuidanceActive Directory ConfigurationVulnerability Scanning

Tecnologías afectadas (1)

Cloudflare — Pingora

CWE

Referencias

JSON original (NVD)

Mostrar
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      "value": "An HTTP request smuggling vulnerability (CWE-444) was found in Pingora's handling of HTTP/1.1 connection upgrades. The issue occurs when a Pingora proxy reads a request containing an Upgrade header, causing the proxy to pass through the rest of the bytes on the connection to a backend before the backend has accepted the upgrade. An attacker can thus directly forward a malicious payload after a request with an Upgrade header to that backend in a way that may be interpreted as a subsequent request header, bypassing proxy-level security controls and enabling cross-user session hijacking.\n\nImpact\n\nThis vulnerability primarily affects standalone Pingora deployments where a Pingora proxy is exposed to external traffic. An attacker could exploit this to:\n\n  *  Bypass proxy-level ACL controls and WAF logic\n\n\n\n\n  *  Poison caches and upstream connections, causing subsequent requests from legitimate users to receive responses intended for smuggled requests\n\n\n\n\n  *  Perform cross-user attacks by hijacking sessions or smuggling requests that appear to originate from the trusted proxy IP\n\n\n\n\nCloudflare's CDN infrastructure was not affected by this vulnerability, as ingress proxies in the CDN stack maintain proper HTTP parsing boundaries and do not prematurely switch to upgraded connection forwarding mode.\n\n\nMitigation:\n\nPingora users should upgrade to Pingora v0.8.0 or higher\n\n\nAs a workaround, users may return an error on requests with the Upgrade header present in their request filter logic in order to stop processing bytes beyond the request header and disable downstream connection reuse."
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      "value": "Se encontró una vulnerabilidad de contrabando de solicitudes HTTP (CWE-444) en el manejo de Pingora de las actualizaciones de conexión HTTP/1.1. El problema ocurre cuando un proxy de Pingora lee una solicitud que contiene un encabezado Upgrade, haciendo que el proxy pase el resto de los bytes de la conexión a un backend antes de que el backend haya aceptado la actualización. Un atacante puede así reenviar directamente una carga útil maliciosa después de una solicitud con un encabezado Upgrade a ese backend de una manera que puede ser interpretada como un encabezado de solicitud subsiguiente, eludiendo los controles de seguridad a nivel de proxy y permitiendo el secuestro de sesión entre usuarios.\n\nImpacto\n\nEsta vulnerabilidad afecta principalmente a implementaciones de Pingora independientes donde un proxy de Pingora está expuesto al tráfico externo. Un atacante podría explotar esto para:\n\n  *  Eludir los controles ACL a nivel de proxy y la lógica WAF\n\n  *  Envenenar cachés y conexiones ascendentes, haciendo que las solicitudes subsiguientes de usuarios legítimos reciban respuestas destinadas a solicitudes de contrabando\n\n  *  Realizar ataques entre usuarios secuestrando sesiones o contrabandeando solicitudes que parecen originarse de la IP del proxy de confianza\n\nLa infraestructura CDN de Cloudflare no se vio afectada por esta vulnerabilidad, ya que los proxies de entrada en la pila CDN mantienen límites de análisis HTTP adecuados y no cambian prematuramente al modo de reenvío de conexión actualizada.\n\nMitigación:\n\nLos usuarios de Pingora deberían actualizar a Pingora v0.8.0 o superior\n\nComo solución alternativa, los usuarios pueden devolver un error en solicitudes con el encabezado Upgrade presente en su lógica de filtro de solicitudes para detener el procesamiento de bytes más allá del encabezado de la solicitud y deshabilitar la reutilización de la conexión descendente."
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