CVE-2026-23739: Sangoma Asterisk

Medium severity, CVSS 6.5. EPSS: 0.2% chance of exploitation in the next 30 days.

Asterisk is an open source private branch exchange and telephony toolkit. Prior to versions 20.7-cert9, 20.18.2, 21.12.1, 22.8.2, and 23.2.2, the ast_xml_open() function in xml.c parses XML documents using libxml with unsafe parsing options that enable entity expansion and XInclude processing. Specifically, it invokes xmlReadFile() with the XML_PARSE_NOENT flag and later processes XIncludes via xmlXIncludeProcess().If any untrusted or user-supplied XML file is passed to this function, it can allow an attacker to trigger XML External Entity (XXE) or XInclude-based local file disclosure, potentially exposing sensitive files from the host system. This can also be triggered in other cases in which the user is able to supply input in xml format that triggers the asterisk process to parse it. This issue has been patched in versions 20.7-cert9, 20.18.2, 21.12.1, 22.8.2, and 23.2.2.

Affected products

• Sangoma Asterisk: before 20.18.2 (fixed in 20.18.2); from 21.0.0, before 21.12.1 (fixed in 21.12.1); from 22.0.0, before 22.8.2 (fixed in 22.8.2); from 23.0.0, before 23.2.2 (fixed in 23.2.2)
• Sangoma Certified Asterisk: up to and including 18.9; version 20.7 only

Published 2026-02-06. Last modified 2026-06-17.