CVE-2026-0792: ALGO 8180 IP Audio Alerter RCE Vulnerability

CVE-2026-0792 Overview

CVE-2026-0792 is a stack-based buffer overflow vulnerability affecting ALGO 8180 IP Audio Alerter devices. This vulnerability allows remote attackers to execute arbitrary code on affected installations without requiring authentication. The flaw exists within the handling of the Alert-Info header of SIP INVITE requests, where the lack of proper validation of user-supplied data length prior to copying it to a fixed-length stack-based buffer enables attackers to achieve remote code execution in the context of the device.

Critical Impact

Unauthenticated remote code execution on ALGO 8180 IP Audio Alerter devices via malicious SIP INVITE requests, potentially allowing complete device compromise.

Affected Products

• ALGO 8180 IP Audio Alerter

Discovery Timeline

• 2026-01-23 - CVE-2026-0792 published to NVD
• 2026-01-26 - Last updated in NVD database

Technical Details for CVE-2026-0792

Vulnerability Analysis

This vulnerability is classified as CWE-121 (Stack-based Buffer Overflow). The vulnerability resides in the SIP (Session Initiation Protocol) implementation of the ALGO 8180 IP Audio Alerter device. When the device processes incoming SIP INVITE requests, it fails to properly validate the length of data contained within the Alert-Info header before copying it to a fixed-length buffer allocated on the stack.

The network-accessible nature of this vulnerability combined with no authentication requirement makes it particularly dangerous for devices exposed to untrusted networks. An attacker who can send SIP traffic to the device can craft a malicious INVITE request containing an oversized Alert-Info header value, causing the buffer to overflow and potentially overwriting critical stack data including return addresses.

Root Cause

The root cause of this vulnerability is improper input validation in the SIP message parsing code. Specifically, the device does not verify that the length of the Alert-Info header value falls within the bounds of the destination buffer before performing the copy operation. This allows user-controlled data to overflow the stack buffer and corrupt adjacent memory, including saved return addresses and other stack frames.

Attack Vector

The attack vector is network-based and requires no authentication or user interaction. An attacker can exploit this vulnerability by:

1. Identifying an ALGO 8180 IP Audio Alerter device accessible via the network (typically on SIP port 5060)
2. Crafting a malicious SIP INVITE request with an oversized Alert-Info header containing attacker-controlled payload data
3. Sending the crafted request to the target device
4. The malformed header data overflows the stack buffer, corrupting adjacent memory
5. By carefully controlling the overflow data, the attacker can overwrite the return address to redirect execution to attacker-supplied shellcode

The vulnerability was originally tracked as ZDI-CAN-28301 by the Zero Day Initiative. For additional technical details, refer to the Zero Day Initiative Advisory ZDI-26-014.

Detection Methods for CVE-2026-0792

Indicators of Compromise

• Unusual or malformed SIP INVITE requests targeting ALGO 8180 devices with abnormally large Alert-Info header values
• Device crashes, reboots, or unexpected behavior following SIP traffic processing
• Evidence of unauthorized code execution or unexpected processes on the device
• Network traffic containing suspicious SIP packets with oversized headers originating from unknown sources

Detection Strategies

• Implement network-based intrusion detection rules to identify SIP INVITE requests with Alert-Info headers exceeding normal size thresholds
• Monitor SIP traffic for malformed or suspicious INVITE messages targeting ALGO 8180 devices
• Deploy packet capture and analysis at network boundaries to detect exploitation attempts
• Configure SIP-aware firewalls to inspect and filter malicious SIP traffic patterns

Monitoring Recommendations

• Enable logging on SIP gateways and proxies to capture detailed information about incoming INVITE requests
• Monitor ALGO 8180 devices for unexpected restarts or service interruptions that may indicate exploitation attempts
• Implement alerting for network anomalies involving SIP protocol traffic to these devices
• Review device logs regularly for signs of attempted exploitation or unauthorized access

How to Mitigate CVE-2026-0792

Immediate Actions Required

• Isolate ALGO 8180 IP Audio Alerter devices from untrusted networks and restrict SIP access to authorized endpoints only
• Implement network segmentation to limit exposure of vulnerable devices
• Deploy SIP-aware firewalls or intrusion prevention systems to filter malicious SIP traffic
• Monitor for vendor patches and apply updates as soon as they become available

Patch Information

Contact ALGO for information regarding firmware updates that address this vulnerability. Monitor the Zero Day Initiative Advisory ZDI-26-014 for updates on patch availability and remediation guidance.

Workarounds

• Restrict network access to ALGO 8180 devices using firewall rules to allow SIP traffic only from trusted sources
• Place vulnerable devices behind a SIP-aware proxy or session border controller that can filter malformed requests
• If the device is not required to accept external SIP connections, disable SIP services or restrict to internal network only
• Implement network access control lists (ACLs) to limit which hosts can communicate with the device on SIP ports

# Example firewall rule to restrict SIP access (iptables)
# Allow SIP traffic only from trusted PBX server
iptables -A INPUT -p udp --dport 5060 -s <trusted_pbx_ip> -j ACCEPT
iptables -A INPUT -p udp --dport 5060 -j DROP
iptables -A INPUT -p tcp --dport 5060 -s <trusted_pbx_ip> -j ACCEPT
iptables -A INPUT -p tcp --dport 5060 -j DROP