What’s Vulnerable › Vulnerabilities
CVE-2026-54282: Starlette: Unvalidated request path concatenated into authority poisons request.url.hostname
- Severity: medium (CVSS 5.3 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.3% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-06-22 · updated 2026-10-25
- Weakness: CWE-706
Description
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.
Affected products
- Kludex starlette: before 1.3.0 — fixed in 1.3.0
How to fix
Upgrade to a fixed version: Kludex starlette 1.3.0. Check the vendor advisory for mitigations.
References
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