Hi,

The following vulnerability was published for qtbase-opensource-src.

CVE-2026-78253[0]:
| Uncontrolled recursion in QXmlStreamReader::readElementText() in Qt
| Group Qt allows attackers to cause a denial of service (application
| crash via stack exhaustion) via a crafted XML document.

This for fixed for qt6-base in 6.11.2+dfsg-5, but appears to also
affect Qt5:

https://codereview.qt-project.org/c/qt/qtbase/+/754345
https://github.com/qt/qtbase/commit/f91c48650443262db9be37d5239ebe0db18e9555 (v6.11.2)


If you fix the vulnerability please also make sure to include the
CVE (Common Vulnerabilities & Exposures) id in your changelog entry.

For further information see:

[0] https://security-tracker.debian.org/tracker/CVE-2026-78253
https://www.cve.org/CVERecord?id=CVE-2026-78253

Please adjust the affected versions in the BTS as needed.