Bug 2531092

Summary: CVE-2026-57163 asterisk: stack overflow parsing a TLS peer certificate's SubjectAltName in GnuTLS backend [epel-all]
Product: [Fedora] Fedora EPEL Reporter: Guilherme de Almeida Suckevicz <gsuckevi>
Component: asteriskAssignee: EPEL Packagers SIG <epel-packagers-sig>
Status: CLOSED NOTABUG QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: urgent Docs Contact:
Priority: urgent    
Version: epel10CC: bennie.joubert, epel-packagers-sig, jsmith.fedora, lemenkov
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["707641c0-3c68-4a57-9599-7ab0482dbbf0"]}
Fixed In Version: Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2026-09-11 19:57:37 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 2528787    

Description Guilherme de Almeida Suckevicz 2026-09-09 17:27:32 UTC 
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.
Comment 1 Peter Lemenkov 2026-09-11 19:49:44 UTC 
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.
Comment 2 Peter Lemenkov 2026-09-11 19:57:37 UTC 
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.