HOMEVULNERABILITIESCVE-2019-18976
HIGH

CVE-2019-18976

CWE-476Published: November 22, 2019· Updated: Jun 17, 2026

7.5
CVSS v3.1

Official Description

An issue was discovered in res_pjsip_t38.c in Sangoma Asterisk through 13.x and Certified Asterisk through 13.21-x. If it receives a re-invite initiating T.38 faxing and has a port of 0 and no c line in the SDP, a NULL pointer dereference and crash will occur. This is different from CVE-2019-18940.

NVD Source

Technical Analysis

CVE-2019-18976 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 · 3 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

ADVISORYhttp://downloads.asterisk.org/pub/security/AST-2019-008.html
ADVISORYhttps://lists.debian.org/debian-lts-announce/2022/04/msg00001.html
ADVISORYhttps://packetstormsecurity.com/files/155436/Asterisk-Project-Security-Advisory-AST-2019-008.html
ADVISORYhttps://seclists.org/fulldisclosure/2019/Nov/20
ADVISORYhttps://www.asterisk.org/downloads/security-advisories
ADVISORYhttps://www.cybersecurity-help.cz/vdb/SB2019112218?affChecked=1
ADVISORYhttp://downloads.asterisk.org/pub/security/AST-2019-008.html
ADVISORYhttps://lists.debian.org/debian-lts-announce/2022/04/msg00001.html
ADVISORYhttps://packetstormsecurity.com/files/155436/Asterisk-Project-Security-Advisory-AST-2019-008.html
ADVISORYhttps://seclists.org/fulldisclosure/2019/Nov/20
ADVISORYhttps://www.asterisk.org/downloads/security-advisories
ADVISORYhttps://www.cybersecurity-help.cz/vdb/SB2019112218?affChecked=1

All References (12)

→
http://downloads.asterisk.org/pub/security/AST-2019-008.htmlVendor Advisory
→
https://lists.debian.org/debian-lts-announce/2022/04/msg00001.htmlMailing List · Third Party Advisory
→
https://packetstormsecurity.com/files/155436/Asterisk-Project-Security-Advisory-AST-2019-008.htmlThird Party Advisory · VDB Entry
→
https://seclists.org/fulldisclosure/2019/Nov/20Mailing List · Third Party Advisory
→
https://www.asterisk.org/downloads/security-advisoriesVendor Advisory
→
https://www.cybersecurity-help.cz/vdb/SB2019112218?affChecked=1Third Party Advisory
→
http://downloads.asterisk.org/pub/security/AST-2019-008.htmlVendor Advisory
→
https://lists.debian.org/debian-lts-announce/2022/04/msg00001.htmlMailing List · Third Party Advisory
→
https://packetstormsecurity.com/files/155436/Asterisk-Project-Security-Advisory-AST-2019-008.htmlThird Party Advisory · VDB Entry
→
https://seclists.org/fulldisclosure/2019/Nov/20Mailing List · Third Party Advisory
→
https://www.asterisk.org/downloads/security-advisoriesVendor Advisory
→
https://www.cybersecurity-help.cz/vdb/SB2019112218?affChecked=1Third Party Advisory

Quick Facts

CVE IDCVE-2019-18976
CVSS Score7.5 / 10
SeverityHIGH
WeaknessCWE-476
CISA KEVNo
Affected2 vendor(s)
PublishedNov 22, 2019

Related CVEs (CWE-476)

CVE-2022-36648
10.0
CVE-2010-2495
10.0
CVE-2017-5668
9.8
CVE-2017-10965
9.8
CVE-2015-8787
9.8
CVE-2016-6604
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2019-18976 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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