Improper Certificate Validation in pjsip - #VU165882
Published: November 11, 2026
Vulnerability identifier: #VU165882
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-295
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass TLS client certificate requirements.
The vulnerability exists due to improper certificate validation in PJSIP's OpenSSL SSL socket backend when resuming sessions, because verification failures are recorded only during full handshakes and resumed sessions report a clean status. A remote attacker can present an untrusted certificate, obtain a session on the refused connection, and resume it to bypass client certificate enforcement, while remaining subject to application-level authentication checks.
Affected software
pjsip
Remediation
Install security update from vendor's website.
pjsip - update to 2.18