PJSIP is a free and open source multimedia communication library written in C language implementing standard based protocols such as SIP, SDP, RTP, STUN, TURN, and ICE. In version 2.10 and earlier, PJSIP transport can be reused if they have the same IP address + port + protocol. However, this is insufficient for secure transport since it lacks remote hostname authentication. Suppose we have created a TLS connection to `sip.foo.com`, which has an IP address `100.1.1.1`. If we want to create a TLS connection to another hostname, say `sip.bar.com`, which has the same IP address, then it will reuse that existing connection, even though `100.1.1.1` does not have certificate to authenticate as `sip.bar.com`. The vulnerability allows for an insecure interaction without user awareness. It affects users who need access to connections to different destinations that translate to the same address, and allows man-in-the-middle attack if attacker can route a connection to another destination such as in the case of DNS spoofing.

Teluu PJSIP version 2.7.1 and earlier contains a Access of Null/Uninitialized Pointer vulnerability in pjmedia SDP parsing that can result in Crash. This attack appear to be exploitable via Sending a specially crafted message. This vulnerability appears to have been fixed in 2.7.2.

Teluu PJSIP version 2.7.1 and earlier contains a Integer Overflow vulnerability in pjmedia SDP parsing that can result in Crash. This attack appear to be exploitable via Sending a specially crafted message. This vulnerability appears to have been fixed in 2.7.2.

An issue was discovered in Teluu pjproject (pjlib and pjlib-util) in PJSIP before 2.7.1. The ioqueue component may issue a double key unregistration after an attacker initiates a socket connection with specific settings and sequences. Such double key unregistration will trigger an integer overflow, which may cause ioqueue backends to reject future key registrations.

An issue was discovered in Teluu pjproject (pjlib and pjlib-util) in PJSIP before 2.7.1. Parsing the numeric header fields in a SIP message (like cseq, ttl, port, etc.) all had the potential to overflow, either causing unintended values to be captured or, if the values were subsequently converted back to strings, a buffer overrun. This will lead to a potential exploit using carefully crafted invalid values.