An issue was discovered in Qt before 5.15.14, 6.x before 6.2.9, and 6.3.x through 6.5.x before 6.5.1. Qt Network incorrectly parses the strict-transport-security (HSTS) header, allowing unencrypted connections to be established, even when explicitly prohibited by the server. This happens if the case used for this header does not exactly match.

References

• https://nvd.nist.gov/vuln/detail/CVE-2023-32762
• qt/qtbase@1b736a8
• https://codereview.qt-project.org/c/qt/qtbase/+/476140
• https://lists.qt-project.org/pipermail/announce/2023-May/000414.html
• https://lists.debian.org/debian-lts-announce/2024/04/msg00027.html