CVE-2026-107457
Description
A flaw was found in Qt. Under certain MQTT version 5 (MQTT 5) connection settings between a client and a server, the QMqttClient class can corrupt memory. A remote attacker could exploit this vulnerability to crash the affected application, resulting in a Denial of Service (DoS).
Statement
A memory corruption vulnerability in Qt's QMqttClient class allows a remote attacker to cause an application crash and denial of service by negotiating specific MQTT 5 connection parameters between client and server.
Mitigation
Configure client applications to connect using MQTT protocol version 3.1.1 rather than MQTT 5 where supported by the broker. If MQTT 5 is required, enforce strict broker-side validation to disallow non-standard or malformed session property negotiation.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.9 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | High | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
Frequently Asked Questions
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