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Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process. PJSIP is a free and open source multimedia communication library written in C. Prior to commit c4a151a, a stack buffer overflow exists in the GnuTLS TLS backend when parsing the Subject Alternative Name extension of a peer certificate (tls_cert_get_info() in ssl_sock_gtls.c). Only GnuTLS builds are affected (--with-gnutls); OpenSSL and Apple SecureTransport/Network.framework builds are not affected. While extracting certificate information after a TLS handshake, an incorrect buffer-size value can cause an oversized SubjectAltName entry to be written past the end of a fixed-size stack buffer. A network-positioned attacker presenting a crafted certificate — a malicious server to a connecting client, or a malicious client to a server that requests certificates — can trigger this during the TLS handshake, before any SIP-level authentication. Impact may range from unexpected application termination to control flow hijack/memory corruption. This issue has been patched via commit c4a151a.
Not applicable to Asterisk as built here. This is a stack buffer overflow in tls_cert_get_info() in ssl_sock_gtls.c, parsing the SubjectAltName extension of a peer certificate. The upstream advisory is explicit that only GnuTLS builds are affected (--with-gnutls), and that OpenSSL and Apple SecureTransport/Network.framework builds are not affected. Asterisk's bundled pjproject is not configured with --with-gnutls. The configure options in third-party/pjproject/Makefile.rules contain no GnuTLS flag, and config_site.h sets PJ_SSL_SOCK_OSSL_USE_THREAD_CB, so the OpenSSL backend is in use. Fixed upstream in pjproject commit c4a151a. Same determination as the Fedora tracker, bug 2531093.
Closing as NOTABUG per the analysis above — the flaw is specific to pjproject's GnuTLS backend, and the bundled build uses OpenSSL. As with the other pjproject CVEs in this batch, this is a build-configuration determination. It would need revisiting if the bundled build were ever configured with --with-gnutls.