CVE-2026-90779: SIPp stack buffer overflow in createAuthHeader()

Executive brief

SIPp is a popular open-source SIP protocol testing tool used to simulate VoIP clients and servers. A malicious SIP server can send a specially crafted authentication challenge that causes a stack buffer overflow in SIPp's authentication handler, crashing the client and potentially allowing remote code execution. This affects organizations using SIPp for VoIP testing and quality assurance.

Technical details

The vulnerability is a stack buffer overflow in the createAuthHeader() function when processing SIP 401 or 407 authentication challenge responses. The flaw occurs when handling oversized algorithm parameters in SIP authentication challenges, allowing an attacker to corrupt stack memory. The attack vector is network-based and requires the victim to connect to a malicious SIP server that sends the crafted challenge. An attacker can trigger a denial of service (process crash) and potentially achieve remote code execution by overflowing the stack buffer with malicious data. The vulnerability affects SIPp through version 3.7.7.

Affected products

• SIPp SIPp through 3.7.7

Timeline

• 2026-09-13: disclosed: CVE-2026-90779 published

References

• https://github.com/SIPp/sipp
• https://github.com/SIPp/sipp/blob/v3.7.7/src/auth.cpp