Risk | Medium |
Patch available | YES |
Number of vulnerabilities | 1 |
CVE-ID | CVE-2021-26717 |
CWE-ID | CWE-20 |
Exploitation vector | Network |
Public exploit | N/A |
Vulnerable software Subscribe |
Asterisk Open Source Server applications / Conferencing, Collaboration and VoIP solutions |
Vendor | Digium (Linux Support Services) |
Security Bulletin
This security bulletin contains one medium risk vulnerability.
EUVDB-ID: #VU50966
Risk: Medium
CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-26717
CWE-ID:
CWE-20 - Improper input validation
Exploit availability: No
DescriptionThe vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.
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.
MitigationInstall update from vendor's website.
Vulnerable software versionsAsterisk Open Source: 1.4.16.1 - 16.6.2
External linkshttp://packetstormsecurity.com/files/161471/Asterisk-Project-Security-Advisory-AST-2021-002.html
http://seclists.org/fulldisclosure/2021/Feb/58
http://downloads.asterisk.org/pub/security/
http://downloads.asterisk.org/pub/security/AST-2021-002.html
http://issues.asterisk.org/jira/browse/ASTERISK-29203
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.