encodeText in QDom in Qt before 6.8.0 has a complex algorithm involving XML string copy and inline replacement of parts of a string (with relocation of later data).
When passing values outside of the expected range to QColorTransferGenericFunction it can cause a denial of service, for example, this can happen when passing a specifically crafted ICC profile to QColorSpace::fromICCProfile.
This issue affects Qt from 6.6.0 through 6.8.3, from 6.9.0 through 6.9.1. This is fixed in 6.8.4 and 6.9.2.
When loading a specifically crafted ICNS format image file in QImage then it will trigger a crash.
This issue affects Qt from versions 6.3.0 through 6.5.9, from 6.6.0 through 6.8.4, 6.9.0. This is fixed in 6.5.10, 6.8.5 and 6.9.1.
An issue was discovered in Qt before 5.15.15, 6.x before 6.2.10, and 6.3.x through 6.5.x before 6.5.3. There are infinite loops in recursive entity expansion.
An issue was discovered in Qt before 5.15.15, 6.x before 6.2.9, and 6.3.x through 6.5.x before 6.5.2. Certificate validation for TLS does not always consider whether the root of a chain is a configured CA certificate.
An issue was discovered in Qt 5.x before 5.15.14, 6.x before 6.2.9, and 6.3.x through 6.5.x before 6.5.1. QDnsLookup has a buffer over-read via a crafted reply from a DNS server.
Qt 5.x before 5.15.6 and 6.x through 6.1.2 has an out-of-bounds write in QOutlineMapper::convertPath (called from QRasterPaintEngine::fill and QPaintEngineEx::stroke).
The GIF decoder in QtGui in Qt before 5.3 allows remote attackers to cause a denial of service (NULL pointer dereference) via invalid width and height values in a GIF image.
Integer overflow in Qt 3.3 before 3.3.7, 4.1 before 4.1.5, and 4.2 before 4.2.1, as used in the KDE khtml library, kdelibs 3.1.3, and possibly other packages, allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted pixmap image.
Qt 6 through 6.6 was discovered to contain a NULL pointer dereference via the function QXcbConnection::initializeAllAtoms(). NOTE: this is disputed because it is not expected that an X application should continue to run when there is arbitrary anomalous behavior from the X server.
Last updated 25 August 2025
In Qt through 5.14.1 the WebSocket implementation accepts up to 2GB for frames and 2GB for messages. Smaller limits cannot be configured. This makes it easier for attackers to cause a denial of service (memory consumption).
Qt before 6.4.3 allows a denial of service via a crafted string when the SQL ODBC driver plugin is used and the size of SQLTCHAR is 4. The affected versions are 5.x before 5.15.13, 6.x before 6.2.8, and 6.3.x before 6.4.3.
An issue was discovered in gui/util/qktxhandler.cpp in Qt before 5.15.17 6.x before 6.2.12 6.3.x through 6.5.x before 6.5.5 and 6.6.x before 6.6.2. A buffer overflow and application crash can occur via a crafted KTX image file.
In Qt before 5.15.14, 6.0.x through 6.2.x before 6.2.9, and 6.3.x through 6.5.x before 6.5.1, QtSvg QSvgFont munitsPerEm initialization is mishandled.
A flaw was found in Qt. An out-of-bounds read vulnerability was found in QRadialFetchSimd in qt/qtbase/src/gui/painting/qdrawhelperp.h in Qt/Qtbase. While rendering and displaying a crafted Scalable Vector Graphics (SVG) file this flaw may lead to an unauthorized memory access. The highest threat from this vulnerability is to data confidentiality and the application availability.
Integer Overflow vulnerability in qsvghandler.cpp in Qt qtsvg versions 5.15.1, 6.0.0, 6.0.2, and 6.2, allows local attackers to cause a denial of service (DoS).
Last updated 25 August 2025
An issue was discovered in Qt 5.11. A malformed PPM image causes a division by zero and a crash in qppmhandler.cpp.
An issue was discovered in Qt before 5.11.3. A malformed SVG image causes a segmentation fault in qsvghandler.cpp.
A possible double free and heap corruption was found in QXmlStream.
Upstream patch:
https://codereview.qt-project.org/#/c/236691/
The UTF-8 decoder in codecs/qutfcodec.cpp in Qt 3.3.8 and 4.2.3 does not reject long UTF-8 sequences as required by the standard, which allows remote attackers to conduct cross-site scripting (XSS) and directory traversal attacks via long sequences that decode to dangerous metacharacters.
QSslSocket in Qt before 4.7.0-rc1 recognizes a wildcard IP address in the subject's Common Name field of an X.509 certificate, which might allow man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority.
Multiple buffer overflows in plugins/imageformats/ico/qicohandler.cpp in the QtBase module in Qt before 4.8.7 and 5.x before 5.4.2 allow remote attackers to cause a denial of service (segmentation fault and crash) and possibly execute arbitrary code via a crafted ICO image.
Multiple buffer overflows in gui/image/qgifhandler.cpp in the QtBase module in Qt before 4.8.7 and 5.x before 5.4.2 allow remote attackers to cause a denial of service (segmentation fault) and possibly execute arbitrary code via a crafted GIF image.
Multiple buffer overflows in gui/image/qbmphandler.cpp in the QtBase module in Qt before 4.8.7 and 5.x before 5.4.2 allow remote attackers to cause a denial of service (segmentation fault and crash) and possibly execute arbitrary code via a crafted BMP image.