Exploited vulnerability · CISA KEV

Is CVE-2026-48710 exploited? Yes: in CISA KEV since 2 Sep 2026

Gociux · Kludex Starlette · data: CISA KEV, CVE record, FIRST EPSS

Yes. CVE-2026-48710, Kludex Starlette HTTP Request/Response Smuggling Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 2 Sep 2026, 99 days after it was published. It affects Kludex Starlette. If you run it, CISA's required action is: 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.

What it is

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.

What to do

1. Check whether you run it. Look for Starlette in your asset inventory, including appliances and cloud images. Stack check lists every exploited Kludex CVE at once.
2. Apply the fix. 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.
3. If you can't patch today, take the affected service off the internet or restrict who can reach it, and check its logs for signs of compromise since 26 May 2026.
4. Get told next time. Email alerts when CISA adds a CVE for Kludex.

References

• nvd.nist.gov/vuln/detail/CVE-2026-48710

Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in September 2026 · act-now radar.