NULL pointer dereference in Certified Asterisk and Asterisk Open Source - CVE-2021-46837
Published: November 22, 2022
Vulnerability identifier: #VU69511
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2021-46837
CWE-ID: CWE-476
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a NULL pointer dereference error. A remote attacker can send an m=image line and zero port in a response to a T.38 re-invite initiated by Asterisk and perform a denial of service (DoS) attack.
Affected software
Certified Asterisk
Asterisk Open Source
Debian Linux
asterisk (Debian package)
Asterisk Open Source
Debian Linux
asterisk (Debian package)
How to mitigate CVE-2021-46837
Install updates from vendor's website.
Certified Asterisk - update to 16.8-cert7
Asterisk Open Source - addressed in versions 17.9.3, 18.3.0
asterisk (Debian package) - update to 1:16.28.0~dfsg-0+deb11u1
Asterisk Open Source - addressed in versions 17.9.3, 18.3.0
asterisk (Debian package) - update to 1:16.28.0~dfsg-0+deb11u1