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.

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).

An issue was discovered in HTTP2 in Qt before 5.15.18, 6.x before 6.2.13, 6.3.x through 6.5.x before 6.5.7, and 6.6.x through 6.7.x before 6.7.3. Code to make security-relevant decisions about an established connection may execute too early, because the encrypted() signal has not yet been emitted and processed..

QAbstractOAuth in Qt Network Authorization in Qt before 5.15.17, 6.x before 6.2.13, 6.3.x through 6.5.x before 6.5.6, and 6.6.x through 6.7.x before 6.7.1 uses only the time to seed the PRNG, which may result in guessable values.

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.

An issue was discovered in the HTTP2 implementation in Qt before 5.15.17, 6.x before 6.2.11, 6.3.x through 6.5.x before 6.5.4, and 6.6.x before 6.6.2. network/access/http2/hpacktable.cpp has an incorrect HPack integer overflow check.

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.

In Qt before 5.15.15, 6.x before 6.2.9, and 6.3.x through 6.5.x before 6.5.2, there can be an application crash in QXmlStreamReader via a crafted XML string that triggers a situation in which a prefix is greater than a length.

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 before 5.15.15, 6.x before 6.2.9, and 6.3.x through 6.5.x before 6.5.1. When a SVG file with an image inside it is rendered, a QTextLayout buffer overflow can be triggered.