CVE-2026-54282: encode starlette

Vulnerability summary

CVE-2026-54282 is a medium (CVSS 5.3) vulnerability in encode starlette. EPSS estimates a 0.27% chance of exploitation in the next 30 days, higher than 18.3% of scored vulnerabilities.

Timeline

1. 22-06-2026
   PublishedVulnerability first disclosed.
2. 22-06-2026
   Last modifiedVulnerability information updated.

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.

• CWE-706Use of Incorrectly-Resolved Name or ReferenceThe product uses a name or reference to access a resource, but the name/reference resolves to a resource that is outside of the intended control sphere.