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CVE-2026-48710

Medium 6.5 Exploited in the wild (KEV)

Confirmed active exploitation — CISA KEV catalog

Name
Kludex Starlette HTTP Request/Response Smuggling Vulnerability
Added to catalog
Remediation due date (US federal)
Required action
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.

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.

Metrics

CVSS 3.1
6.5 (MEDIUM) Score source: NVD CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
EPSS — exploit probability
70% (percentile: 99) as of 1 November 2026
CWE
CWE-444, CWE-1289

Affected products

encode: starlette; redhat: ai inference server; redhat: ansible automation platform; redhat: migration toolkit for applications; redhat: openshift ai; redhat: openshift lightspeed; redhat: satellite; redhat: enterprise linux ai

References