A NULL pointer dereference vulnerability in the Qt Framework QDomDocument::setContent() XML parsing path of the Qt XML module (qtbase) has been discovered and has been assigned the CVE id CVE-2026-82292.
Affected versions: from Qt 4.1.0 to Qt 6.8.8, from Qt 6.9.0 to Qt 6.11.2
Affected status unknown before Qt 4.1.0
Impact: The issue occurs when XML containing characters that are invalid under XML 1.0 is parsed through QDomDocument::setContent() while invalidDataPolicy is set to QDomImplementation::ReturnNullNode. The document node factory returns a null node, and the DOM builder then dereferences that pointer without a null check. Worst case is an application crash (denial of service). There is no impact on confidentiality or integrity.
CVSS 4.0 Score: 1.9 / LOW
Vector String: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/R:U/RE:L
Mitigation: Validate XML data separately before passing it to QDomDocument::setContent(). Only parse XML originating from trusted sources. Applications that do not require QDomImplementation::ReturnNullNode can additionally avoid the issue by leaving invalidDataPolicy at its default setting.
Solution: Apply the following patch, or update to Qt 6.8.9 or Qt 6.11.3 or later.
Patches:
dev: https://codereview.qt-project.org/c/qt/qtbase/+/757771
Qt 6.11: https://codereview.qt-project.org/c/qt/qtbase/+/765680 or https://download.qt.io/official_releases/qt/6.11/CVE-2026-82292-qtbase-6.11.diff
Qt 6.8: https://codereview.qt-project.org/c/qt/tqtc-qtbase/+/766406 or https://download.qt.io/archive/qt/6.8/CVE-2026-82292-qtbase-6.8.diff
