CVE-2026-48061 Litestar: AllowedHostsMiddleware bypasses host validation via client-controlled X-Forwarded-Host header
Attackers can bypass host validation in Litestar by spoofing the X-Forwarded-Host header, enabling password reset poisoning and cache poisoning attacks.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-48061?
CVE-2026-48061 is a medium-severity vulnerability in litestar-org litestar, published on 3 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Litestar is an Asynchronous Server Gateway Interface (ASGI) framework. In versions prior to 2.22.0, an attacker can bypass the allowed hosts validation by omitting the Host header and supplying an X-Forwarded-Host header set to a whitelisted domain. The AllowedHostsMiddleware trusts the X-Forwarded-Host header as a fallback when the Host header is absent. Since X-Forwarded-Host is a client-controllable header, this enables host header injection attacks such as password reset poisoning, cache poisoning, and server-side request routing manipulation. Any application using AllowedHostsConfig is affected when deployed without a reverse proxy that strips X-Forwarded-Host, or when accepting HTTP/1.0 connections. This issue has been fixed in version 2.22.0.
Weakness: CWE-644
Which versions are affected by CVE-2026-48061?
3 open source packages ship an affected version, including litestar.
| Package | Affected | Fixed in |
|---|---|---|
litestar PyPI | All versions | 2.22.0 |
litestar PyPI | All versions | 2.22.0 |
litestar PyPI | All versions | 2.22.0 |
How do I fix CVE-2026-48061?
Upgrade litestar to 2.22.0 or later.
Is CVE-2026-48061 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-48061 exists.
Sources
Also known as GHSA-3qmc-cj7q-62hv, PYSEC-2026-2603.