HIGH
CVE-2021-26712
NVD-CWE-OtherPublished: February 18, 2021· Updated: Jun 17, 2026
7.5
CVSS v3.1
Official 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.
Technical Analysis
CVE-2021-26712 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected Vendors & Products
digium2 product(s)
asteriskcertified asterisk
Source: NVD CPE · 2 total CPE entries
Exploit & PoC Resources
NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.
Official Patches & Advisories
All References (10)
→
→
http://seclists.org/fulldisclosure/2021/Feb/59Mailing List · Third Party Advisory
→
https://downloads.asterisk.org/pub/security/Vendor Advisory
→
→
https://issues.asterisk.org/jira/browse/ASTERISK-29260Issue Tracking · Patch · Vendor Advisory
→
→
http://seclists.org/fulldisclosure/2021/Feb/59Mailing List · Third Party Advisory
→
https://downloads.asterisk.org/pub/security/Vendor Advisory
→
→
https://issues.asterisk.org/jira/browse/ASTERISK-29260Issue Tracking · Patch · Vendor Advisory
Quick Facts
CVE IDCVE-2021-26712
CVSS Score7.5 / 10
SeverityHIGH
WeaknessNVD-CWE-Other
CISA KEVNo
Affected1 vendor(s)
PublishedFeb 18, 2021
Related CVEs (NVD-CWE-Other)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-26712 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.