Public vulnerability disclosure

CVE-2026-107457

Memory corruption vulnerability in QMqttClient impacts Qt MQTT

publishedCWE-787CWE-129

A memory corruption vulnerability in the QMqttClient class of the Qt MQTT module. Under certain MQTT 5 connection settings between client and server, QMqttClient may corrupt memory, which can cause the application to crash.

Investigate in Cyber JSON Markdown

Technical severity2.3 lowCVSS 4.0 · CNA: Qt

Published2026-11-02Source updated 2026-11-02

Collected2026-11-021 attributed source

Fixes and workarounds

No remediation reported in collected sources.

Missing remediation information is not evidence that no patch exists.

Affected products and versions

Affected products, source version ranges and reporting authorities
Product	Versions	Authority
Qt qt	≥ 5.12.0; ≤ 6.8.8 (affected, python) ≥ 6.9.0; ≤ 6.11.2 (affected, python) ≥ 0; < 5.12.0 (unaffected, python) Other versions: unaffected	CNA: Qt

Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.

CVSS assessments

CVSS scores, vectors and reporting authorities
Version / score	Vector	Authority
4.0 / 2.3 low	`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/R:U/RE:L/U:Green`	CNA: Qt

Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

References

https://wiki.qt.io/List_of_known_vulnerabilities_in_Qt_products#CVE-2026-107457:CNA: Qt · vendor-advisory
https://codereview.qt-project.org/c/qt/qtmqtt/+/762286CNA: Qt · patch