CVE-2026-23739 Asterisk xml.c uses unsafe XML_PARSE_NOENT leading to potential XXE Injection
Attackers can exploit unsafe XML parsing in Asterisk to disclose sensitive local files via XXE or XInclude attacks.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-23739?
CVE-2026-23739 is a low-severity vulnerability in asterisk, published on 6 Feb 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-611
Which versions are affected by CVE-2026-23739?
It affects 2 products.
Products include Sangoma Asterisk, Sangoma Certified Asterisk.
How do I fix CVE-2026-23739?
Upgrade to a fixed version.
Is CVE-2026-23739 being exploited?
There is no known exploitation of CVE-2026-23739 in the wild and no public exploit code.
Other vulnerabilities in asterisk
- CVE-2024-57520 Path traversal in n/a
- CVE-2025-47779 Using malformed From header can forge identity with ";" or NULL in name portion
- CVE-2025-57767 Asterisk can crash from a specifically malformed Authorization header in an incoming SIP request
- CVE-2022-37325 Memory corruption in n/a
- CVE-2025-1131 Asterisk Unsafe Shell Sourcing in safe_asterisk Leads to Local Privilege Escalation
Sources
Also known as DEBIAN-CVE-2026-23739, GHSA-85x7-54wr-vh42, UBUNTU-CVE-2026-23739.