HOMEVULNERABILITIESCVE-2021-32558
HIGH

CVE-2021-32558

CWE-74Published: July 30, 2021· Updated: Jun 17, 2026

7.5
CVSS v3.1

Official Description

An issue was discovered in Sangoma Asterisk 13.x before 13.38.3, 16.x before 16.19.1, 17.x before 17.9.4, and 18.x before 18.5.1, and Certified Asterisk before 16.8-cert10. If the IAX2 channel driver receives a packet that contains an unsupported media format, a crash can occur.

NVD Source

Technical Analysis

CVE-2021-32558 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

Debian1 product(s)
debian linux
digium2 product(s)
asteriskcertified asterisk
Source: NVD CPE · 4 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

PATCHhttp://packetstormsecurity.com/files/163639/Asterisk-Project-Security-Advisory-AST-2021-008.html
PATCHhttp://seclists.org/fulldisclosure/2021/Jul/49
PATCHhttps://downloads.asterisk.org/pub/security/AST-2021-008.html
PATCHhttps://issues.asterisk.org/jira/browse/ASTERISK-29392
PATCHhttp://packetstormsecurity.com/files/163639/Asterisk-Project-Security-Advisory-AST-2021-008.html
PATCHhttp://seclists.org/fulldisclosure/2021/Jul/49
PATCHhttps://downloads.asterisk.org/pub/security/AST-2021-008.html
PATCHhttps://issues.asterisk.org/jira/browse/ASTERISK-29392
ADVISORYhttps://lists.debian.org/debian-lts-announce/2021/08/msg00005.html
ADVISORYhttps://www.debian.org/security/2021/dsa-4999
ADVISORYhttps://lists.debian.org/debian-lts-announce/2021/08/msg00005.html
ADVISORYhttps://www.debian.org/security/2021/dsa-4999

All References (12)

→
http://packetstormsecurity.com/files/163639/Asterisk-Project-Security-Advisory-AST-2021-008.htmlPatch · Third Party Advisory · VDB Entry
→
http://seclists.org/fulldisclosure/2021/Jul/49Mailing List · Patch · Third Party Advisory
→
https://downloads.asterisk.org/pub/security/AST-2021-008.htmlPatch · Vendor Advisory
→
https://issues.asterisk.org/jira/browse/ASTERISK-29392Exploit · Issue Tracking · Patch · Vendor Advisory
→
https://lists.debian.org/debian-lts-announce/2021/08/msg00005.htmlMailing List · Third Party Advisory
→
https://www.debian.org/security/2021/dsa-4999Third Party Advisory
→
http://packetstormsecurity.com/files/163639/Asterisk-Project-Security-Advisory-AST-2021-008.htmlPatch · Third Party Advisory · VDB Entry
→
http://seclists.org/fulldisclosure/2021/Jul/49Mailing List · Patch · Third Party Advisory
→
https://downloads.asterisk.org/pub/security/AST-2021-008.htmlPatch · Vendor Advisory
→
https://issues.asterisk.org/jira/browse/ASTERISK-29392Exploit · Issue Tracking · Patch · Vendor Advisory
→
https://lists.debian.org/debian-lts-announce/2021/08/msg00005.htmlMailing List · Third Party Advisory
→
https://www.debian.org/security/2021/dsa-4999Third Party Advisory

Quick Facts

CVE IDCVE-2021-32558
CVSS Score7.5 / 10
SeverityHIGH
WeaknessCWE-74
CISA KEVNo
Affected2 vendor(s)
PublishedJul 30, 2021

Related CVEs (CWE-74)

CVE-2023-30547
10.0
CVE-2023-32314
10.0
CVE-2025-20265
10.0
CVE-2020-26282
10.0
CVE-2026-56699
10.0
CVE-2026-44182
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-32558 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.
← All Vulnerabilities·Search for CVE-2021-32558·NVD