CVE-2026-23739: Asterisk xml.c uses unsafe XML_PARSE_NOENT leading to potential XXE Injection
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 astxmlopen() 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 XMLPARSENOENT 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 Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-23739?
CVE-2026-23739 is classified as a high-severity vulnerability due to its potential to allow XML External Entity (XXE) injection.
How do I fix CVE-2026-23739?
To fix CVE-2026-23739, upgrade to Asterisk versions 20.7-cert10, 20.18.3, 21.12.2, 22.8.3, or 23.2.3 or later.
What specific software is affected by CVE-2026-23739?
CVE-2026-23739 affects Asterisk versions prior to 20.7-cert9, 20.18.2, 21.12.1, 22.8.2, and 23.2.2.
What is XXE injection related to CVE-2026-23739?
XXE injection is a vulnerability that allows an attacker to exploit XML input to gain unauthorized access to data.
What security practices can help mitigate CVE-2026-23739?
Employing secure XML parsing configurations and ensuring software is regularly updated can help mitigate the risks associated with CVE-2026-23739.