What's Happening?
A critical vulnerability has been identified in Grandstream's GXP1600 series phones, which could enable attackers to intercept calls. The flaw, tracked as CVE-2026-2329, is a stack-based buffer overflow that allows unauthenticated attackers to execute
code with root privileges on the affected devices. These phones are primarily used by small-to-medium businesses. Exploiting this vulnerability could allow attackers to extract sensitive information, such as local and SIP account credentials, facilitating call interception and eavesdropping. Rapid7, a cybersecurity firm, reported the vulnerability and noted that while exploitation requires significant skill, it lowers the security barrier for potential attackers. The vulnerability was disclosed to Grandstream in January, and a patched firmware version has been released.
Why It's Important?
The discovery of this vulnerability is significant as it highlights the potential risks to business communications, particularly for small-to-medium enterprises that rely on these devices. The ability to intercept calls could lead to the exposure of sensitive business information, including contracts and legal strategies, which could have severe implications for affected companies. This incident underscores the importance of robust cybersecurity measures and timely updates to protect against such vulnerabilities. Businesses using these devices need to be aware of the risks and ensure they apply the necessary patches to safeguard their communications.
What's Next?
Organizations using Grandstream's GXP1600 series phones should immediately update to the latest firmware to mitigate the risk of exploitation. Cybersecurity experts may continue to monitor for any signs of exploitation in the wild and provide further guidance on securing VoIP systems. Additionally, this incident may prompt other manufacturers to review their products for similar vulnerabilities, potentially leading to broader industry-wide security improvements.









