CVE Vulnerabilities


Use After Free

Published: Feb 01, 2022 | Modified: Feb 04, 2022
CVSS 3.x
CVSS 2.x

Element Desktop is a Matrix client for desktop platforms with Element Web at its core. Element Desktop before 1.9.7 is vulnerable to a remote program execution bug with user interaction. The exploit is non-trivial and requires clicking on a malicious link, followed by another button click. To the best of our knowledge, the vulnerability has never been exploited in the wild. If you are using Element Desktop < 1.9.7, we recommend upgrading at your earliest convenience. If successfully exploited, the vulnerability allows an attacker to specify a file path of a binary on the victims computer which then gets executed. Notably, the attacker does not have the ability to specify program arguments. However, in certain unspecified configurations, the attacker may be able to specify an URI instead of a file path which then gets handled using standard platform mechanisms. These may allow exploiting further vulnerabilities in those mechanisms, potentially leading to arbitrary code execution.


Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.

Affected Software

Name Vendor Start Version End Version
Desktop Element * 1.9.7 (excluding)

Extended Description

The use of previously-freed memory can have any number of adverse consequences, ranging from the corruption of valid data to the execution of arbitrary code, depending on the instantiation and timing of the flaw. The simplest way data corruption may occur involves the system’s reuse of the freed memory. Use-after-free errors have two common and sometimes overlapping causes:

In this scenario, the memory in question is allocated to another pointer validly at some point after it has been freed. The original pointer to the freed memory is used again and points to somewhere within the new allocation. As the data is changed, it corrupts the validly used memory; this induces undefined behavior in the process. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.

Potential Mitigations