Bug 2437909 (CVE-2026-23739)

Summary: CVE-2026-23739 Asterisk: Asterisk: Local file disclosure via unsafe XML parsing
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: low    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Asterisk. The `ast_xml_open()` function in `xml.c` processes XML documents using `libxml` with unsafe parsing options, enabling entity expansion and XInclude processing. A remote attacker can exploit this by providing specially crafted XML input, leading to XML External Entity (XXE) or XInclude-based local file disclosure. This vulnerability could allow the attacker to expose sensitive files from the host system.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2437959, 2437961, 2437963, 2437964    
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Description OSIDB Bzimport 2026-02-09 11:13:17 UTC 
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.