CVE-2026-48710 Kludex Starlette: software flaw
In plain words: A mistake in the software that attackers have found a way to abuse. Depends on the product — see the description and the vendor advisory.
Confirmed exploited by CISA on · US federal patch deadline Sep 16, 2026
What to do
- Install Kludex's security update for Starlette. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Keep a list of every internet-facing server you run so nothing is forgotten.
- Patch anything in this catalog first, ahead of normal patch cycles.
- Put admin and file-transfer apps behind a VPN or single sign-on instead of the open internet.
Who is affected
Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.
What's at risk: Mass data theft and ransomware: a single flaw in a file-transfer or email server has exposed thousands of organisations at once.
The details
- Official name
- Kludex Starlette HTTP Request/Response Smuggling Vulnerability
- Product
- Kludex Starlette
- CISA 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.
- Type of flaw
- Software flaw (CWE-444)
- Confirmed exploited
- Sep 2, 2026
- US federal patch deadline
- Sep 16, 2026
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Answering about CVE-2026-48710 ·
Questions about CVE-2026-48710
Is CVE-2026-48710 being exploited?
Yes. CISA added CVE-2026-48710 to its Known Exploited Vulnerabilities catalog on Sep 2, 2026, which means there is reliable evidence of real-world attacks.
How do I fix CVE-2026-48710?
Install Kludex's security update for Starlette. If no update exists, follow the vendor's workaround or stop using the product until one ships. Keep a list of every internet-facing server you run so nothing is forgotten.
Am I affected by CVE-2026-48710?
Only if you use Kludex Starlette. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.