Vulnerability · Published Jun 22, 2026 · Assigned by GitHub_M
CVE-2026-54282Starlette: Unvalidated request path concatenated into authority poisons request.url.hostname
Low 3.7
In plain English
A low-severity security flaw in starlette from Kludex. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 20% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | starlette | 0.26.1-1+deb12u2 | DEBIAN-CVE-2026-54282 |
| Debian:13 | starlette | 0.46.1-3+deb13u3 | DEBIAN-CVE-2026-54282 |
| Debian:14 | starlette | 1.3.1-1 | DEBIAN-CVE-2026-54282 |
| PyPI | starlette | 1.3.0 | GHSA-jp82-jpqv-5vv3 |
| PyPI | starlette | 1.3.0 | PYSEC-2026-248 |
| Ubuntu:22.04:LTS | starlette | no fix listed | UBUNTU-CVE-2026-54282 |
| Ubuntu:24.04:LTS | starlette | no fix listed | UBUNTU-CVE-2026-54282 |
| Ubuntu:25.10 | starlette | no fix listed | UBUNTU-CVE-2026-54282 |
| Ubuntu:26.04:LTS | starlette | no fix listed | UBUNTU-CVE-2026-54282 |
| Ubuntu:26.10 | starlette | no fix listed | UBUNTU-CVE-2026-54282 |
Affected products (as reported)
Weakness: CWE-706 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
References
- https://github.com/Kludex/starlette/security/advisories/GHSA-jp82-jpqv-5vv3 x_refsource_CONFIRM