CVE-2026-9499
An out-of-bounds read (buffer over-read) vulnerability exists in QTextCodec::codecForName() in Qt.
Overview
CVE-2026-9499 is a known-severity vulnerability. It was published on July 21, 2026.
Technical description
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.
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
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Frequently asked questions
What is CVE-2026-9499?
CVE-2026-9499 is a known-severity vulnerability. It was published on July 21, 2026.
How severe is CVE-2026-9499?
CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.
How do I fix or remediate CVE-2026-9499?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-9499?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-9499 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.