Wazuh is a free and open source platform used for threat prevention, detection, and response. Prior to 4.12.0, a buffer over-read occurs in w_expression_match() when strlen() is called on str_test, because the corresponding buffer is not being properly NULL terminated during its allocation in OS_CleanMSG(). A compromised agent can cause a READ operation beyond the end of the allocated buffer (which may contain sensitive information) by sending a specially crafted message to the wazuh manager. An attacker who is able to craft and send an agent message to the wazuh manager can cause a buffer over-read and potentially access sensitive data. This vulnerability is fixed in 4.12.0.