Use-after-free in pjsip - #VU156286
Published: October 21, 2026
Vulnerability identifier: #VU156286
CSH Severity: Medium
CVSS v4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service by crashing an application.
The vulnerability exists due to a use-after-free in pjsua_acc_send_response() in pjsip/src/pjsua-lib/pjsua_acc.c when an application sends a deferred MESSAGE response after the associated transaction has been destroyed. A remote attacker can send a MESSAGE request over TCP or TLS and close the connection before the application responds to cause access to the freed transaction and crash the application.
The affected deferred-response behavior requires auto_repond_sip_message to be disabled; this option is enabled by default.
Affected software
pjsip
Remediation
Install security update from vendor's website.
pjsip - update to 2.18