CVE-2026-45705: Opensips

Medium severity, CVSS 5.3. EPSS: 0.5% chance of exploitation in the next 30 days.

OpenSIPS is a Session Initiation Protocol (SIP) server implementation. In versions prior to 3.6.6 and 4.0.0-rc1, the find_line_delimiter() function in the multipart body parser performs an out-of-bounds read via strncmp() when searching for MIME boundary delimiters. After finding a -- pattern near the end of the body, the function compares delimiter.len bytes (typically 20-70) starting from a position at or past the logical end of the body buffer, reading past the body boundary. The bug triggers when a SIP message has Content-Type: multipart/mixed with a boundary parameter and its body contains -- within two to three bytes of the body's end without being followed by the actual boundary delimiter. This issue has been fixed in versions 3.6.6 and 4.0.0-rc1.

Affected products

• Opensips Opensips: from 3.4.0, before 3.6.6 (fixed in 3.6.6); from 4.0.0-beta, before 4.0.0-rc1 (fixed in 4.0.0-rc1)

Published 2026-08-05. Last modified 2026-09-08.