CVE-2026-48710

Medium

Kludex Starlette HTTP Request/Response Smuggling Vulnerability

6.5 CVSS v3.1

Published: May 26, 2026
Updated: Oct 1, 2026
Vendor: Encode, Redhat
Affected versions: See affected products
Weakness: CWE-444, CWE-1289

Summary

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.

Severity

Medium (6.5)

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected products

Encode Starlette >= 0.8.3, < 1.0.1
Redhat Ai Inference Server >= 3.3.0, <= 3.3.5
Redhat Ansible Automation Platform 2.6
Redhat Ansible Automation Platform 2.7
Redhat Migration Toolkit For Applications < 8.2.0
Redhat Openshift Ai >= 3.3, < 3.3.5
Redhat Openshift Ai >= 3.4, < 3.4.2
Redhat Openshift Lightspeed
Redhat Satellite 6.17
Redhat Satellite 6.18
Redhat Satellite 6.19
Redhat Enterprise Linux Ai 3.0

Exploitation status

Actively exploited

Listed in the CISA Known Exploited Vulnerabilities catalog on Sep 2, 2026. Federal remediation due: Sep 16, 2026.

Technical details

Technical analysis has not been written for this record yet.

Mitigation & remediation

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.