Asterisk Project Security Advisory - Product Asterisk Summary Re-invite with T.38 and malformed SDP causes crash. Nature of Advisory Remote Crash Susceptibility Remote Authenticated Sessions Severity Minor Exploits Known No Reported On November 07, 2019 Reported By Salah Ahmed Posted On November 21, 2019 Last Updated On November 21, 2019 Advisory Contact bford AT sangoma DOT com CVE Name CVE-2019-18976 Description If Asterisk receives a re-invite initiating T.38 faxing and has a port of 0 and no c line in the SDP, a crash will occur. Modules Affected res_pjsip_t38.c Resolution If T.38 faxing is not needed, then the â??t38_udptlâ?? configuration option in pjsip.conf can be set to â??noâ?? to disable the functionality. This option automatically defaults to â??noâ?? and would have to be manually turned on to experience this crash. If T.38 faxing is needed, then Asterisk should be upgraded to a fixed version. Affected Versions Product Release Series Asterisk Open Source 13.x All versions Certified Asterisk 13.21 All versions Corrected In Product Release Asterisk Open Source 13.29.2 Certified Asterisk 13.21-cert5 Patches SVN URL Revision http://downloads.asterisk.org/pub/security/AST-2019-008-13.diff Asterisk 13 http://downloads.asterisk.org/pub/security/AST-2019-008-13.21.diff Certified Asterisk 13.21-cert5 Links https://issues.asterisk.org/jira/browse/ASTERISK-28612 Asterisk Project Security Advisories are posted at http://www.asterisk.org/security This document may be superseded by later versions; if so, the latest version will be posted at http://downloads.digium.com/pub/security/.pdf and http://downloads.digium.com/pub/security/.html Revision History Date Editor Revisions Made November 12, 2019 Ben Ford Initial Revision November 21, 2019 Ben Ford Added â??Posted Onâ?? date Asterisk Project Security Advisory - Copyright © 2019 Digium, Inc. All Rights Reserved. Permission is hereby granted to distribute and publish this advisory in its original, unaltered form.