CVE-2019-18976

Name: CVE-2019-18976
Creator: NVD / NIST
Published: 2019-11-22T17:15:11.833+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 6.68%

Last modified Jun 17, 2026

CVE-2019-18976 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 6.68% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

6.68%

93.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-476

Affected Software

Vendor	Product	Versions
Digium	Asterisk	>= 13.0.0, <= 13.29.1
Digium	Certified Asterisk	13.21
Debian	Debian Linux	9.0

References

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

Timeline

Published: Nov 22, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-18976?

How severe is CVE-2019-18976?

CVE-2019-18976 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 6.68% probability of exploitation in the next 30 days.

How do I fix CVE-2019-18976?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2019-18976?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST