AUGUST 16, 2026
Live Feed
Back to database
Case File

CVE-2026-45103

HIGH · CVSS 7.5 EPSS 0.33% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-08-04 · Last synced 2026-08-16

CyberRota Analysis

AI-Generated

OpenSIPS versions prior to 3.6.6 and 4.0.0-rc1 are vulnerable due to an improper handling of the Content-Length header in the TCP message framing layer, which can lead to SIP message smuggling. This vulnerability allows unauthenticated attackers to bypass security policies and manipulate SIP messages over TCP-based transports, potentially compromising the integrity of communications. Organizations using affected versions of OpenSIPS should prioritize upgrading to the patched versions to mitigate this high-severity risk.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-45103
Severity
HIGH
CVSS
7.5
EPSS
0.33%

Original NVD Description

OpenSIPS is a Session Initiation Protocol (SIP) server implementation. In versions prior to 3.6.6 and 4.0.0-rc1, the TCP message framing layer parses the Content-Length header using unsigned int arithmetic with no overflow check. When an attacker sends a Content-Length value that overflows unsigned int (e.g., 4294967296), the framing layer computes a wrapped-around value (e.g., 0) and splits the TCP stream at the wrong boundary, causing the body of the first SIP message to be processed as a separate message and enabling SIP message smuggling. Because Content-Length is parsed in the transport layer before authentication, an unauthenticated, network-based attacker can smuggle arbitrary SIP messages over any TCP-based transport (proto_tcp, proto_tls, proto_ws, proto_wss) on any instance with TCP enabled, with no routing-script preconditions. This allows smuggled messages to bypass front-end SBC/proxy security policies, inherit the connection's authentication context, and evade rate limiting. This issue has been fixed in versions 3.6.6 and 4.0.0-rc1.