What’s Vulnerable › Vulnerabilities

CVE-2021-26712

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-02-18 · updated 2026-06-17

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.

Affected products

• Digium Asterisk: from 13.0.0 through 13.38.2; from 16.0.0 before 16.16.1; from 17.0.0 before 17.9.2; from 18.0 before 18.2.1 — fixed in 16.16.1, 17.9.2, 18.2.1
• Digium Certified Asterisk: 16.8, 16.8-cert1-rc1, 16.8-cert1-rc2, 16.8-cert1-rc3, 16.8-cert1-rc4, 16.8-cert2 (+7)

How to fix

Upgrade to a fixed version: Digium Asterisk 16.16.1, 17.9.2, 18.2.1. Check the vendor advisory for mitigations.

References

• http://packetstormsecurity.com/files/161473/Asterisk-Project-Security-Advisory-AST-2021-003.html
• http://seclists.org/fulldisclosure/2021/Feb/59
• https://downloads.asterisk.org/pub/security/
• https://downloads.asterisk.org/pub/security/AST-2021-003.html
• https://issues.asterisk.org/jira/browse/ASTERISK-29260
• http://packetstormsecurity.com/files/161473/Asterisk-Project-Security-Advisory-AST-2021-003.html
• http://seclists.org/fulldisclosure/2021/Feb/59
• https://downloads.asterisk.org/pub/security/
• https://downloads.asterisk.org/pub/security/AST-2021-003.html
• https://issues.asterisk.org/jira/browse/ASTERISK-29260

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