CVE-2026-57163 PJSIP: Stack overflow parsing a TLS peer certificate's SubjectAltName in GnuTLS backend
A stack buffer overflow in PJSIP's GnuTLS backend allows remote attackers to cause memory corruption or crashes via crafted TLS certificates.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-57163?
CVE-2026-57163 is a high-severity memory corruption vulnerability in pjsip pjproject, published on 4 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-121
Which versions are affected by CVE-2026-57163?
It affects 1 product.
Products include Teluu Pjsip.
How do I fix CVE-2026-57163?
No fix has been published for CVE-2026-57163 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-57163 being exploited?
There is no known exploitation of CVE-2026-57163 in the wild and no public exploit code.
Other vulnerabilities in pjsip pjproject
- CVE-2023-38703 PJSIP has use-after-free vulnerability in SRTP media transport
- CVE-2022-39269 Media transport downgrade from the secure version (SRTP) to non-secure (RTP) in pjsip
- CVE-2026-57161 PJSIP: Stack overflow handling Service-Route headers in a registration response
- CVE-2026-57162 PJSIP: Stack overflow parsing SDP a=crypto attributes
- CVE-2026-57159 PJSIP: SDP parser out-of-bounds write in remote payload-type map maintenance
Sources
Also known as DEBIAN-CVE-2026-57163, GHSA-jm2j-6rg6-qvwx, UBUNTU-CVE-2026-57163.