# CVE-2026-107457: Memory corruption vulnerability in QMqttClient impacts Qt MQTT

Status: published. Published: 2026-11-02. Updated: 2026-11-02.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- qt / Qt: ≥ 5.12.0; ≤ 6.8.8 (affected, python); ≥ 6.9.0; ≤ 6.11.2 (affected, python); ≥ 0; < 5.12.0 (unaffected, python). Source: CNA: Qt

## Severity and prioritization

- CVSS 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; source: CNA: Qt

- CVSS 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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:U/V:X/RE:L/U:Green; source: NVD: a59d8014-47c4-4630-ab43-e1b13cbe58e3

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-787, CWE-129

## 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/+/762286 (CNA: Qt; patch)

- https://codereview.qt-project.org/c/qt/qtmqtt/+/762286 (a59d8014-47c4-4630-ab43-e1b13cbe58e3)

- https://wiki.qt.io/List_of_known_vulnerabilities_in_Qt_products#CVE-2026-107457: (a59d8014-47c4-4630-ab43-e1b13cbe58e3)

## Provenance

- CNA: Qt: https://www.cve.org/CVERecord?id=CVE-2026-107457; retrieved 2026-11-02; source updated 2026-11-02

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-107457; retrieved 2026-11-02; source updated 2026-11-02

Revision: ac946497d68e5993fb971d11fcef5a3220aad394c70d1776bac6024c5c4d6036

Canonical: https://y2.dev/cve/CVE-2026-107457