CVE entry · CVE-2026-48710
CVE-2026-48710: Kludex Starlette HTTP Request/Response Smuggling Vulnerability
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.
- Actively exploited: added to CISA’s KEV catalog on September 2, 2026.
- Use by ransomware: not established so far.
- Remediation deadline for US federal agencies: September 16, 2026.
Description from CISA’s KEV catalog.
What to do
- Check whether your estate includes Kludex Starlette, including internet-facing devices.
- Apply the vendor’s patch or mitigations (references below). Failing that, isolate the product or stop using it, as CISA requires of US federal agencies.
- An exploited vulnerability has often been used before it was fixed: look for signs of compromise, especially on internet-facing devices.