Medium [CVE-2026-54282] Information disclosure due to improper HTTP request path validation

Starlette is a lightweight ASGI framework/toolkit. Prior to 1.3.0, the HTTP request path is not validated before being used to reconstruct request.url.

Because request.url is rebuilt by concatenating {scheme}://{host}{path} and re-parsing the result, a path that does not begin with / (for example @google.com) moves the authority boundary during re-parsing, so request.url.hostname and request.url.netloc become attacker-controlled.

Code that reads request.url.hostname (rather than the Host header or scope) can therefore be misled into trusting an attacker-supplied host. This vulnerability is fixed in 1.3.0.

A remote attacker could craft a malicious HTTP request path that does not begin with a forward slash, causing the framework to misinterpret the authority boundary.

This could lead to `request.url.hostname` and `request.url.netloc` becoming attacker-controlled, potentially misleading applications that rely on these values into trusting an attacker-supplied host. Red Hat rates this issue as having Low impact for Red Hat AI products.

Bundled Starlette versions in Red Hat OpenShift AI, Red Hat AI Inference Server, and Red Hat Enterprise Linux AI are either not vulnerable or the flawed path validation is not reachable in supported deployments. Red Hat severity: Low — CVSS 4.8 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N).

Weakness: CWE-1286.