CVE-2026-9499 Affecting qtbase-opensource-src package, versions <5.15.19+dfsg-4


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.52% (43rd percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-QTBASEOPENSOURCESRC-18137934
  • published22 Jul 2026
  • disclosed21 Jul 2026

Introduced: 21 Jul 2026

CVE-2026-9499  (opens in a new tab)

How to fix?

Upgrade Debian:unstable qtbase-opensource-src to version 5.15.19+dfsg-4 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream qtbase-opensource-src package and not the qtbase-opensource-src package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1