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OpenAdvisories
Critical · 9.2 CVE-2025-6338 EUVD-2025-34743GHSA-m4hj-jpxf-jhjp

Possible denial of service with multiple incoming connections to a Schannel based server with a TLS backend

Published Oct 16, 2025 · Updated Jul 29, 2026 · Assigned by TQtC

Vendor: Qt Project Product: Qt

Description

There is an incomplete cleanup vulnerability in Qt Network's Schannel support on Windows which can lead to a Denial of Service over a long period.

This issue affects Qt from 5.15.0 through 6.8.3, from 6.9.0 before 6.9.2.

Affected products

VendorProductAffectedFixed
Qt Qt 5.15.0 – ≤ 6.8.3, 6.9.0 – < 6.9.2 6.9.2

Advisories 1

References