CVE-2026-84975 Security feature bypass in pjproject
Attackers can bypass TLS hostname verification in PJSIP to impersonate servers and steal SIP credentials when server verification is enabled.
- 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-2026-84975?
CVE-2026-84975 is a high-severity vulnerability in pjsip pjproject, published on 18 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. In 2.17 and earlier, the OpenSSL and GnuTLS backends in pjlib/src/pj/ssl_sock_ossl.c and pjlib/src/pj/ssl_sock_gtls.c copy DNS SubjectAltName values with string functions that recalculate their length and truncate an embedded NUL byte. With server verification enabled through --tls-verify-server for the PJSIP TLS/SIPS transport, a certificate containing a DNS SubjectAltName formed from the target hostname prefix followed by an embedded NUL and an attacker-controlled suffix can therefore be accepted for the prefix hostname. An attacker who possesses such a certificate from a trusted issuer and can intercept the connection can impersonate the target server, complete the SIP session, and receive REGISTER credentials. The mbedTLS backend is not affected because it preserves the explicit string length. No fixed version is available as of this review.
Which versions are affected by CVE-2026-84975?
It affects 1 product.
Products include Teluu Pjsip.
How do I fix CVE-2026-84975?
No fix has been published for CVE-2026-84975 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-84975 being exploited?
There is no known exploitation of CVE-2026-84975 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-2026-57163 PJSIP: Stack overflow parsing a TLS peer certificate's SubjectAltName in GnuTLS backend
Sources
Also known as DEBIAN-CVE-2026-84975, GHSA-382p-87mh-r3q8, UBUNTU-CVE-2026-84975.