CVE-2026-9499
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
Summary
An out-of-bounds read (buffer over-read) vulnerability exists in QTextCodec::codecForName() in Qt. When the function is called with a QByteArray that is not NUL-terminated (for example, one created with QByteArray::fromRawData()), the codec-name matching routine reads past the end of the supplied buffer. In most cases this results in an incorrect text codec being selected; in the worst case, if the over-read reaches unmapped memory, the process crashes (denial of service). The over-read is bounded by the length of the longest codec-name candidate, and the out-of-bounds bytes are only compared internally against Qt's fixed list of codec names, so no data is disclosed to an attacker. Applications that do not pass non-NUL-terminated QByteArrays to QTextCodec::codecForName() are not exposed. The affected code resides in the Qt5Compat module from Qt 6.0.0 onward, and in Qt Core (qtbase) in Qt 4.x and Qt 5.x.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Qt | Qt | 6.0.0 < 6.8.8 | affected |
| Qt | Qt | 6.9.0 < 6.11.1 | affected |
| Qt | Qt | 4.0.0 < 6.0.0 | affected |
Weaknesses
- CWE-125: CWE-125 Out-of-bounds Read
References
- https://codereview.qt-project.org/c/qt/qt5compat/+/723911
- https://codereview.qt-project.org/c/qt/qt5compat/+/724348
- https://codereview.qt-project.org/c/qt/qt5compat/+/724995
- https://codereview.qt-project.org/c/qt/tqtc-qt5compat/+/725112
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