This vulnerability is a stack‑based buffer overflow triggered by the Replaces header in SIP INVITE requests. Because the device does not validate the length of user‑supplied data before copying it to a fixed‑length buffer, a crafted header can overwrite critical control data on the stack. The flaw enables remote attackers to inject code and execute it with the privileges of the device, leading to full compromise. The lack of an authentication requirement exacerbates the danger, allowing anyone on the network to launch the attack.

The affected equipment is the ALGO 8180 IP Audio Alerter system, specifically firmware version 5.5 and likely earlier releases. All units of this product that receive SIP INVITE traffic are at risk. 5.5 is listed in the CPE for the device firmware, indicating that the issue exists in that revision. Users should verify the firmware version in use and determine if they are running a vulnerable build.

The CVSS score of 9.8 classifies the flaw as critical, while the EPSS score of less than 1% shows a very low chance of exploitation in the wild. The vulnerability is not currently in the CISA Known Exploited Vulnerabilities catalog, suggesting no known active attacks. Nonetheless, the attack vector is network‑based, does not require authentication, and can be performed by anyone with access to the device’s SIP port. The potential impact remains complete loss of device security, so the overall risk is high.