CVE Watch1 oct 2026

CVE-2026-48710

Kludex Starlette HTTP Request/Response Smuggling Vulnerability

CVSS

6.5

Medio

EPSS

7.1%

p94

KEV

SÍ

2 sept 2026

Exploit Today

0-100

Publicado: 26 may 2026 · Última mod.: 1 oct 2026 · CWE-444 · CWE-1289

EPSS · 30d

7.1%EPSS · 30 días36.3%

2026-09-202026-10-17

Ficha del catálogo KEV

Producto

Kludex / Starlette

Vulnerabilidad

Kludex Starlette HTTP Request/Response Smuggling Vulnerability

Añadido a KEV

2 sept 2026

Remediar antes de

16 sept 2026

Uso conocido en ransomware

Descripción resumida

Kludex Starlette contains a HTTP request/response smuggling vulnerability that could allow attackers to inject paths into the host part, prepending the actual path leading to issues such as authentication bypass when the authentication depends on the reconstructed URL’s path. This vulnerability could be chaned with CVE-2026-42271.

Acción requerida

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Notas

This vulnerability affects an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: https://github.com/Kludex/starlette/security/advisories/GHSA-86qp-5c8j-p5mr ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-48710

Descripción técnica

Starlette is a lightweight ASGI framework/toolkit. Prior to version 1.0.1, the HTTP `Host` request header was not validated before being used to reconstruct `request.url`. Because the routing algorithm relies on the raw HTTP path while `request.url` is rebuilt from the `Host` header, a malformed header could make `request.url.path` differ from the path that was actually requested. Middleware and endpoints that apply security restrictions based on `request.url` (rather than the raw `scope` path) could therefore be bypassed. Users should upgrade to a version greater than or equal to version 1.0.1, which validates the `Host` header against the grammar of RFC 9112 §3.2 / RFC 3986 §3.2.2 when constructing `request.url` and falls back to `scope["server"]` for malformed values.

Referencias oficiales

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