Kludex Starlette HTTP Request/Response Smuggling Vulnerability (CVE-2026-48710)
Severity: medium · Patch status: patched · Since 2026-09-02 · CVE-2026-48710
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. CISA added CVE-2026-48710 to its Known Exploited Vulnerabilities catalog on Sep 2, 2026, which means attackers are exploiting it in the wild.
What to do
- 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.
- US federal agencies must remediate by Sep 16, 2026 (BOD 22-01); treat that as the outer limit.
Sources
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