CVE-2026-77803

3.6 LOW

Published 2026-10-05 · Updated 2026-10-06

AI analysis for this CVE has not been generated yet. Raw NVD data is shown below.

NVD description

In Progress® Telerik® Fiddler® Classic for Windows, versions prior to v6.0.20262.10021, front-end request desynchronization is possible in the proxy request forwarding component. A request that contains both a Content-Length and a Transfer-Encoding header is forwarded with both headers present, while Fiddler frames the body using Transfer-Encoding only. The remaining bytes on the reused client connection are then parsed as a separate pipelined request, so a local threat actor with low privileges can cause a single malformed request to be split into two requests forwarded to the origin server and receive an additional smuggled response, without requiring a vulnerable server.

CVSS vector

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N

Weaknesses

CWE-444

All references

https://docs.telerik.com/fiddler/knowledge-base/kb-security-front-end-desynchronization-cve-2026-77803

Source data: NVD (nvd.nist.gov), public domain. Exploit-DB.ai adds local AI analysis for defensive use only.

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