CVE-2026-48710
Kludex starlette, Red Hat AI Inference Server 3.3, Red Hat Ansible Automation Platform 2.6
Published 26 May 2026 · updated 1 Oct 2026 · Analyzed
Exploited in the wild
CISA added this to its Known Exploited Vulnerabilities catalog on 2 Sept 2026, with a remediation deadline of 16 Sept 2026 for US federal agencies.
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.
References
- badhost.org/ · Mitigation, Third Party Advisory
- github.com/Kludex/starlette/commit/764dab0dcfb9033d75442d7a359645c9f94648c6 · Patch
- github.com/Kludex/starlette/security/advisories/GHSA-86qp-5c8j-p5mr · Vendor Advisory
- github.com/pypa/advisory-database/tree/main/vulns/starlette/PYSEC-2026-161.yaml · Third Party Advisory
- ostif.org/disclosing-the-badhost-vulnerability-in-starlette · Mitigation, Third Party Advisory
- www.secwest.net/starlette · Exploit, Mitigation, Third Party Advisory
- www.x41-dsec.de/lab/advisories/x41-2026-002-starlette · Exploit, Mitigation, Third Party Advisory
- access.redhat.com/errata/RHSA-2026:22992 · Third Party Advisory
- access.redhat.com/errata/RHSA-2026:22993 · Third Party Advisory
- access.redhat.com/errata/RHSA-2026:23346 · Third Party Advisory
- access.redhat.com/errata/RHSA-2026:24866 · Third Party Advisory
- access.redhat.com/errata/RHSA-2026:26226 · Third Party Advisory
- access.redhat.com/errata/RHSA-2026:30088 · Third Party Advisory
- access.redhat.com/errata/RHSA-2026:30089 · Third Party Advisory
- access.redhat.com/errata/RHSA-2026:34456 · Third Party Advisory
- access.redhat.com/errata/RHSA-2026:34526 · Third Party Advisory
- access.redhat.com/errata/RHSA-2026:34532 · Third Party Advisory
- access.redhat.com/errata/RHSA-2026:37275 · Third Party Advisory
- access.redhat.com/errata/RHSA-2026:43038 · Third Party Advisory
- access.redhat.com/errata/RHSA-2026:44696 · Third Party Advisory
- access.redhat.com/errata/RHSA-2026:51357 · Third Party Advisory
- access.redhat.com/errata/RHSA-2026:60520 · Third Party Advisory
- access.redhat.com/errata/RHSA-2026:63337 · Third Party Advisory
- access.redhat.com/security/cve/CVE-2026-48710 · Third Party Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2481742 · Issue Tracking, Third Party Advisory