CVE-2026-47221
Full vulnerability record from the local CVENow database.
Description
Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.18.0 until 1.35.13, 1.36.9, 1.37.5, and 1.38.3, the router filter contains a null pointer dereference vulnerability when handling HTTP 303 (See Other) internal redirects for body-less non-GET/HEAD requests. When a POST, PUT, DELETE, or PATCH request without a body is sent to a route configured with internal redirect policy that includes 303 in redirect_response_codes, and the upstream responds with HTTP 303, the redirect handling code attempts to drain a request body buffer that was never allocated. This results in a segmentation fault that crashes the entire Envoy process. When route configured with internal_redirect_policy including 303 in redirect_response_codes and upstream must return HTTP 303 response, an unauthenticated attacker can exploit this to cause complete denial of service, terminating all active connections. This vulnerability is fixed in 1.35.13, 1.36.9, 1.37.5, and 1.38.3.
Severity
HIGH
CVSS score
7.5
(v3.1)
Vulnerability status
Analyzed
Source identifier
Published
2026-06-26 18:16:59.087000
Last modified
2026-10-25 17:10:00.197000
View original CVE JSON
{
"id": "CVE-2026-47221",
"sourceIdentifier": "[email protected]",
"published": "2026-06-26T18:16:59.087",
"lastModified": "2026-10-25T17:10:00.197",
"vulnStatus": "Analyzed",
"cveTags": [],
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"value": "Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.18.0 until 1.35.13, 1.36.9, 1.37.5, and 1.38.3, the router filter contains a null pointer dereference vulnerability when handling HTTP 303 (See Other) internal redirects for body-less non-GET/HEAD requests. When a POST, PUT, DELETE, or PATCH request without a body is sent to a route configured with internal redirect policy that includes 303 in redirect_response_codes, and the upstream responds with HTTP 303, the redirect handling code attempts to drain a request body buffer that was never allocated. This results in a segmentation fault that crashes the entire Envoy process. When route configured with internal_redirect_policy including 303 in redirect_response_codes and upstream must return HTTP 303 response, an unauthenticated attacker can exploit this to cause complete denial of service, terminating all active connections. This vulnerability is fixed in 1.35.13, 1.36.9, 1.37.5, and 1.38.3."
},
{
"lang": "es",
"value": "Envoy es un proxy de borde y de servicio de código abierto diseñado para aplicaciones nativas de la nube. Desde 1.18.0 hasta 1.35.13, 1.36.9, 1.37.5 y 1.38.3, el filtro del router contiene una vulnerabilidad de desreferencia de puntero nulo al manejar redirecciones internas HTTP 303 (Ver Otros) para solicitudes sin cuerpo que no son GET/HEAD. Cuando una solicitud POST, PUT, DELETE o PATCH sin cuerpo se envía a una ruta configurada con una política de redirección interna que incluye 303 en redirect_response_codes, y el origen responde con HTTP 303, el código de manejo de redirección intenta vaciar un búfer de cuerpo de solicitud que nunca fue asignado. Esto resulta en un fallo de segmentación que bloquea todo el proceso de Envoy. Cuando una ruta configurada con internal_redirect_policy que incluye 303 en redirect_response_codes y el origen debe devolver una respuesta HTTP 303, un atacante no autenticado puede explotar esto para causar una denegación de servicio completa, terminando todas las conexiones activas. Esta vulnerabilidad se corrige en 1.35.13, 1.36.9, 1.37.5 y 1.38.3."
}
],
"affected": [
{
"source": "[email protected]",
"affectedData": [
{
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"product": "envoy",
"versions": [
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"baseScore": 5.9,
"baseSeverity": "MEDIUM",
"attackVector": "NETWORK",
"attackComplexity": "HIGH",
"privilegesRequired": "NONE",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"availabilityImpact": "HIGH"
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"type": "Primary",
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"id": "CVE-2026-47221",
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"weaknesses": [
{
"source": "[email protected]",
"type": "Secondary",
"description": [
{
"lang": "en",
"value": "CWE-476"
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"configurations": [
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"nodes": [
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"source": "[email protected]",
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