CVE-2025-68274: SIPGO is Vulnerable to Response DoS via Nil Pointer Dereference

A nil pointer dereference vulnerability was discovered in the SIPGO library’s NewResponseFromRequest function that affects all normal SIP operations. The vulnerability allows remote attackers to crash any SIP application by sending a single malformed SIP request without a To header.

The vulnerability occurs when SIP message parsing succeeds for a request missing the To header, but the response creation code assumes the To header exists without proper nil checks. This affects routine operations like call setup, authentication, and message handling - not just error cases.

Note: This vulnerability affects all SIP applications using the sipgo library, not just specific configurations or edge cases, as long as they make use of the NewResponseFromRequest function.