CVE-2021-26712

Name: CVE-2021-26712
Creator: NVD / NIST
Published: 2021-02-18T21:15:11.447+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 3.59%

Last modified Jun 17, 2026

CVE-2021-26712 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Incorrect access controls in res_srtp.c in Sangoma Asterisk 13.38.1, 16.16.0, 17.9.1, and 18.2.0 and Certified Asterisk 16.8-cert5 allow a remote unauthenticated attacker to prematurely terminate secure calls by replaying SRTP packets.. EPSS estimates a 3.59% chance of exploitation in the next 30 days.

Description

Incorrect access controls in res_srtp.c in Sangoma Asterisk 13.38.1, 16.16.0, 17.9.1, and 18.2.0 and Certified Asterisk 16.8-cert5 allow a remote unauthenticated attacker to prematurely terminate secure calls by replaying SRTP packets.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

3.59%

88.0th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Digium	Asterisk	>= 13.0.0, <= 13.38.2
Digium	Asterisk	>= 16.0.0, < 16.16.1
Digium	Asterisk	>= 17.0.0, < 17.9.2
Digium	Asterisk	>= 18.0, < 18.2.1
Digium	Certified Asterisk	16.8

References

http://packetstormsecurity.com/files/161473/Asterisk-Project-Security-Advisory-AST-2021-003.htmlThird Party Advisory
http://seclists.org/fulldisclosure/2021/Feb/59Mailing List, Third Party Advisory
https://downloads.asterisk.org/pub/security/Vendor Advisory
https://downloads.asterisk.org/pub/security/AST-2021-003.htmlVendor Advisory
https://issues.asterisk.org/jira/browse/ASTERISK-29260Issue Tracking, Patch, Vendor Advisory
http://packetstormsecurity.com/files/161473/Asterisk-Project-Security-Advisory-AST-2021-003.htmlThird Party Advisory
http://seclists.org/fulldisclosure/2021/Feb/59Mailing List, Third Party Advisory
https://downloads.asterisk.org/pub/security/Vendor Advisory
https://downloads.asterisk.org/pub/security/AST-2021-003.htmlVendor Advisory
https://issues.asterisk.org/jira/browse/ASTERISK-29260Issue Tracking, Patch, Vendor Advisory

Timeline

Published: Feb 18, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-26712?

How severe is CVE-2021-26712?

CVE-2021-26712 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 3.59% probability of exploitation in the next 30 days.

How do I fix CVE-2021-26712?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-26712?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST