Security advisory: Qt SVG

A recent potential divide by zero in Qt SVG has been reported and has been assigned the CVE id CVE-2023-32573.

In QSvgFont, the m_unitsPerEm variable initialization is mishandled so if a SVG file that uses font-face without units-per-em set is passed to QSvgRenderer to render then it can trigger a division by zero.

Solution: Apply the following patch or update to Qt 5.15.14, Qt 6.2.9 or Qt 6.5.1

Patches:

dev: <https://codereview.qt-project.org/c/qt/qtsvg/+/474093&gt;
Qt 6.5: <https://codereview.qt-project.org/c/qt/qtsvg/+/474404&gt; or <https://download.qt.io/official_releases/qt/6.5/CVE-2023-32573-qtsvg-6.5.diff&gt;
Qt 6.2: <https://download.qt.io/official_releases/qt/6.2/CVE-2023-32573-qtsvg-6.2.diff&gt;
Qt 5.15: <https://download.qt.io/official_releases/qt/5.15/CVE-2023-32573-qtsvg-5.15.diff&gt;