PJSIP pjproject versions 2.16 and earlier contain a stack buffer overflow in the pjsip_auth_create_digest2() function. The vulnerability arises because the function copies credential data using cred_info->data.slen as the length without verifying it against the fixed buffer size (128 bytes). If data.slen exceeds the expected digest string length, it can overflow the ha1 stack buffer, leading to potential memory corruption. This issue is tracked as CVE-2026-40892 and classified under CWE-121 (Stack-based Buffer Overflow). The vulnerability is remotely exploitable without authentication and requires no user interaction, contributing to its high severity rating (CVSS 8.1).

Successful exploitation of this vulnerability could result in memory corruption due to stack buffer overflow, which may lead to application crashes or potentially arbitrary code execution. The vulnerability is remotely exploitable without privileges or user interaction, increasing its risk. However, there are no known exploits in the wild at this time.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no official fix or patch links are provided, users should monitor the vendor's communications for updates. Until a patch is available, consider restricting access to affected services or applying any available workarounds recommended by the vendor once published.