CVE-2026-48710
Description
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.
How to fix
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.
CISA due date: Sep 16, 2026- encode starlette1.0.1 or later
- redhat migration_toolkit_for_applications8.2.0 or later
- redhat openshift_ai3.3.5, 3.4.2 or later
- starlette1.0.1 or later
- access.redhat.com/errata/RHSA-2026:30089
- access.redhat.com/errata/RHSA-2026:30088
- access.redhat.com/errata/RHSA-2026:24866
- access.redhat.com/errata/RHSA-2026:23346
- access.redhat.com/errata/RHSA-2026:43038
- access.redhat.com/errata/RHSA-2026:37275
- access.redhat.com/errata/RHSA-2026:60520
- access.redhat.com/errata/RHSA-2026:34456
- access.redhat.com/errata/RHSA-2026:44696
- access.redhat.com/errata/RHSA-2026:22993
- access.redhat.com/errata/RHSA-2026:26226
- access.redhat.com/errata/RHSA-2026:51357
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| encode starlette | 0.8.3 ≤ v < 1.0.1 | 1.0.1 |
| redhat ai_inference_server | 3.3.0 ≤ v ≤ 3.3.5 | — |
| redhat ansible_automation_platform | 2.6, 2.7 | — |
| redhat migration_toolkit_for_applications | v < 8.2.0 | 8.2.0 |
| redhat openshift_ai | 3.3 ≤ v < 3.3.5, 3.4 ≤ v < 3.4.2 | 3.3.5, 3.4.2 |
| redhat openshift_lightspeed | No range specified | — |
| redhat satellite | 6.17, 6.18, 6.19 | — |
| redhat enterprise_linux_ai | 3.0 | — |
| starlettePyPI | v < 1.0.1 | 1.0.1 |
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