Medium · published May 27, 2026
CVSS calls it medium at 6.5. It is confirmed in active exploitation. It sits in the 94.2th percentile for exploit probability.
Starlette is a lightweight ASGI framework/toolkit. Prior to version 1.0.1, the HTTP `Host` request header was not validated before being used to reconstruct `request.url`. Because the routing algorithm relies on the raw HTTP path while `request.url` is rebuilt from the `Host` header, a malformed header could make `request.url.path` differ from the path that was actually requested. Middleware and endpoints that apply security restrictions based on `request.url` (rather than the raw `scope` path) could therefore be bypassed. Users should upgrade to a version greater than or equal to version 1.0.1, which validates the `Host` header against the grammar of RFC 9112 §3.2 / RFC 3986 §3.2.2 when constructing `request.url` and falls back to `scope["server"]` for malformed values.
| Product | Versions | Fixed in |
|---|---|---|
| encode/starlette | ≥ 0.8.3, < 1.0.1 | 1.0.1 |
| redhat/ai_inference_server | ≥ 3.3.0, ≤ 3.3.5 | — |
| redhat/ansible_automation_platform | all versions | — |
| redhat/ansible_automation_platform | all versions | — |
| redhat/migration_toolkit_for_applications | < 8.2.0 | 8.2.0 |
| redhat/openshift_ai | ≥ 3.3, < 3.3.5 | 3.3.5 |
| redhat/openshift_ai | ≥ 3.4, < 3.4.2 | 3.4.2 |
| redhat/openshift_lightspeed | all versions | — |
| redhat/satellite | all versions | — |
| redhat/satellite | all versions | — |
| redhat/satellite | all versions | — |
| redhat/enterprise_linux_ai | all versions | — |