CVE-2026-94370: qt qt_for_mcus Double Free

Vulnerability summary

CVE-2026-94370 is a medium (CVSS 6.5) Double Free vulnerability in qt qt_for_mcus. EPSS estimates a 0.33% chance of exploitation in the next 30 days, higher than 24.9% of scored vulnerabilities.

Timeline

1. 14-10-2026
   PublishedVulnerability first disclosed.
2. 14-10-2026
   Last modifiedVulnerability information updated.

Description

A defect in the Qt for MCUs core string handling causes heap memory corruption. When an application passes text into Qt Quick Ultralite using the public Qul::String interface type, and that text is held in a std::string, the conversion to the internal string type copies the pointer without taking ownership of it. Two objects then release the same memory, producing a double free, an invalid free, or a use-after-free.

• CWE-415Double FreeThe product calls free() twice on the same memory address.
• CWE-416Use After FreeThe product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
• CWE-590Free of Memory not on the HeapThe product calls free() on a pointer to memory that was not allocated using associated heap allocation functions such as malloc(), calloc(), or realloc().
• CWE-665Improper InitializationThe product does not initialize or incorrectly initializes a resource, which might leave the resource in an unexpected state when it is accessed or used.