HOMEVULNERABILITIESCVE-2021-46837
MEDIUM

CVE-2021-46837

CWE-476Published: August 30, 2022· Updated: Jun 17, 2026

6.5
CVSS v3.1

Official Description

res_pjsip_t38 in Sangoma Asterisk 16.x before 16.16.2, 17.x before 17.9.3, and 18.x before 18.2.2, and Certified Asterisk before 16.8-cert7, allows an attacker to trigger a crash by sending an m=image line and zero port in a response to a T.38 re-invite initiated by Asterisk. This is a re-occurrence of the CVE-2019-15297 symptoms but not for exactly the same reason. The crash occurs because there is an append operation relative to the active topology, but this should instead be a replace operation.

NVD Source

Technical Analysis

CVE-2021-46837 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 6.5.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.Low
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected Vendors & Products

asterisk1 product(s)
certified asterisk
Debian1 product(s)
debian linux
digium1 product(s)
asterisk
Source: NVD CPE · 5 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

ADVISORYhttps://downloads.asterisk.org/pub/security/AST-2021-006.html
ADVISORYhttps://lists.debian.org/debian-lts-announce/2022/11/msg00021.html
ADVISORYhttps://www.debian.org/security/2022/dsa-5285
ADVISORYhttps://downloads.asterisk.org/pub/security/AST-2021-006.html
ADVISORYhttps://lists.debian.org/debian-lts-announce/2022/11/msg00021.html
ADVISORYhttps://www.debian.org/security/2022/dsa-5285

All References (6)

→
https://downloads.asterisk.org/pub/security/AST-2021-006.htmlVendor Advisory
→
https://lists.debian.org/debian-lts-announce/2022/11/msg00021.htmlMailing List · Third Party Advisory
→
https://www.debian.org/security/2022/dsa-5285Third Party Advisory
→
https://downloads.asterisk.org/pub/security/AST-2021-006.htmlVendor Advisory
→
https://lists.debian.org/debian-lts-announce/2022/11/msg00021.htmlMailing List · Third Party Advisory
→
https://www.debian.org/security/2022/dsa-5285Third Party Advisory

Quick Facts

CVE IDCVE-2021-46837
CVSS Score6.5 / 10
SeverityMEDIUM
WeaknessCWE-476
CISA KEVNo
Affected3 vendor(s)
PublishedAug 30, 2022

Related CVEs (CWE-476)

CVE-2022-36648
10.0
CVE-2010-2495
10.0
CVE-2022-26097
9.8
CVE-2022-26093
9.8
CVE-2022-26094
9.8
CVE-2022-26096
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-46837 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.
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