CVE-2026-48710
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.
Actively exploited
- In the CISA exploited-vulnerabilities catalogue since Sep 2, 2026
- US federal agencies must remediate it by Sep 16, 2026 (BOD 22-01)
- Attacked 1 day before the vulnerability was made public
- Used in ransomware campaigns
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Source: CISA KEV · Sep 2, 2026 Sep 2, 2026 Aug 27, 2026 Aug 26, 2026 May 26, 2026
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:NAffected products
| Vendors | Prodotto | Versioni |
|---|---|---|
| encode | starlette | < 1.0.1 |
| redhat | ai inference server | <= 3.3.5 |
| redhat | ansible automation platform | 2.6 |
| redhat | migration toolkit for applications | < 8.2.0 |
| redhat | openshift ai | < 3.3.5 |
| redhat | openshift lightspeed | - |
| redhat | satellite | 6.17 |
| redhat | enterprise linux ai | 3.0 |
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