Kludex · Starlette
CVE-2026-48710
Kludex Starlette HTTP Request/Response Smuggling Vulnerability
CISA KEV record
- CISA date added
- 2026-09-02
- CISA due date
- 2026-09-16
- Known ransomware use
- Unknown
NVD risk context
6.5 MEDIUM
CVSS is a technical severity score. CISA’s KEV status remains the evidence that this vulnerability is known to be exploited.
Description
Kludex Starlette contains a HTTP request/response smuggling vulnerability that could allow attackers to inject paths into the host part, prepending the actual path leading to issues such as authentication bypass when the authentication depends on the reconstructed URL’s path. This vulnerability could be chaned with CVE-2026-42271.
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.
NVD reference index
Vendor and remediation references
NVD has tagged these sources as vendor advisories, patches, mitigations, or release notes.
- https://badhost.org ↗
- https://github.com/Kludex/starlette/commit/764dab0dcfb9033d75442d7a359645c9f94648c6 ↗
- https://github.com/Kludex/starlette/security/advisories/GHSA-86qp-5c8j-p5mr ↗
- https://ostif.org/disclosing-the-badhost-vulnerability-in-starlette ↗
- https://www.secwest.net/starlette ↗
- https://www.x41-dsec.de/lab/advisories/x41-2026-002-starlette ↗
Other NVD references (23)
- https://github.com/pypa/advisory-database/tree/main/vulns/starlette/PYSEC-2026-161.yaml ↗
- https://access.redhat.com/errata/RHSA-2026:22992 ↗
- https://access.redhat.com/errata/RHSA-2026:22993 ↗
- https://access.redhat.com/errata/RHSA-2026:23346 ↗
- https://access.redhat.com/errata/RHSA-2026:24866 ↗
- https://access.redhat.com/errata/RHSA-2026:26226 ↗
- https://access.redhat.com/errata/RHSA-2026:30088 ↗
- https://access.redhat.com/errata/RHSA-2026:30089 ↗
- https://access.redhat.com/errata/RHSA-2026:34456 ↗
- https://access.redhat.com/errata/RHSA-2026:34526 ↗
- https://access.redhat.com/errata/RHSA-2026:34532 ↗
- https://access.redhat.com/errata/RHSA-2026:37275 ↗
- https://access.redhat.com/errata/RHSA-2026:43038 ↗
- https://access.redhat.com/errata/RHSA-2026:44696 ↗
- https://access.redhat.com/errata/RHSA-2026:51357 ↗
- https://access.redhat.com/errata/RHSA-2026:60520 ↗
- https://access.redhat.com/errata/RHSA-2026:63337 ↗
- https://access.redhat.com/security/cve/CVE-2026-48710 ↗
- https://bugzilla.redhat.com/show_bug.cgi?id=2481742 ↗
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-48710.json ↗
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-48710 ↗
- https://www.wiz.io/blog/ai-infrastructure-honeypot ↗
- https:/www.microsoft.com/en-us/security/blog/2026/08/26/when-ai-infrastructure-becomes-target-securing-gateways-control-points ↗
MITRE CWE context
CWE classification
The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.
View official MITRE CWE details ↗NVD record timing
NVD record timeline
These dates describe NVD’s record, not CISA’s KEV addition or remediation due date.
- NVD published
- May 26, 2026, 10:16 PM UTC When NVD first published this CVE record.
- NVD last updated
- Sep 04, 2026, 03:59 PM UTC When NVD last changed its analysis or record data.
Advanced: view the technical CVSS vector
This standardized code is intended for security tools and technical analysts. The plain-language risk summary above explains its main points.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
CISA notes
This vulnerability affects an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: https://github.com/Kludex/starlette/security/advisories/GHSA-86qp-5c8j-p5mr ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-48710
- https://github.com/Kludex/starlette/security/advisories/GHSA-86qp-5c8j-p5mr
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
- https://nvd.nist.gov/vuln/detail/CVE-2026-48710