Vulnerability DatabaseCVE-2021-26717
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CVE-2021-26717
Published:February 18, 2021
Updated:July 21, 2026
An issue was discovered in Sangoma Asterisk 16.x before 16.16.1, 17.x before 17.9.2, and 18.x before 18.2.1 and Certified Asterisk before 16.8-cert6. When re-negotiating for T.38, if the initial remote response was delayed just enough, Asterisk would send both audio and T.38 in the SDP. If this happened, and the remote responded with a declined T.38 stream, then Asterisk would crash.
Related Resources (8)
https://downloads.asterisk.org/pub/security/AST-2021-002.html
https://downloads.asterisk.org/pub/security/
http://seclists.org/fulldisclosure/2021/Feb/58
https://people.canonical.com/~ubuntu-security/cve/CVE-2021-26717
https://issues.asterisk.org/jira/browse/ASTERISK-29203
http://packetstormsecurity.com/files/161471/Asterisk-Project-Security-Advisory-AST-2021-002.html
https://security-tracker.debian.org/tracker/CVE-2021-26717
https://security.alpinelinux.org/vuln/CVE-2021-26717
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CVSS v4
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
EPSS
Base Score:
2.18