Hi, There is a "Use After Free" vulnerability in Qt's QHttp2ProtocolHandler in the QtNetwork module. This only affects HTTP/2 handling, HTTP handling is not affected by this at all. This happens due to a race condition between how QHttp2Stream uploads the body of a POST request and the simultaneous handling of HTTP error responses.
This has been assigned the CVE id CVE-2025-5991. Affected versions: Qt version 6.9.0. This is fixed in 6.9.1. Impact: This only affects HTTP/2 handling, HTTP handling is not affected by this at all. This happens due to a race condition between how QHttp2Stream uploads the body of a POST request and the simultaneous handling of HTTP error responses. Vulnerability Score: CVSS v4.0: 2.1 Solution: Apply the following patch for Qt 6.9.0 or update to 6.9.1. 6.9: https://download.qt.io/official_releases/qt/6.9/CVE-2025-5999-qtbase-6.9.patch or https://codereview.qt-project.org/c/qt/qtbase/+/646572 Kind regards, Andy -- Andy Shaw, Director, Customer Services - SQS The Qt Company _______________________________________________ Announce mailing list annou...@qt-project.org https://lists.qt-project.org/listinfo/announce -- Development mailing list Development@qt-project.org https://lists.qt-project.org/listinfo/development
