# CVE-2026-86144: libxml2 xinclude parseFlags not propagated

Source: https://junglewise.ai/threats/cve-2026-86144-libxml2-xinclude-parseflags-not-propagated  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-05. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-86144 · Severity: medium · CVSS 5.6 · Published 2026-09-05

libxml2 is a widely-used XML parsing library embedded in countless applications and operating systems. A flaw in its XML Include (xinclude) functionality fails to apply security restrictions (parseFlags) when processing included XML files, potentially allowing attackers to bypass protections against external network access, trigger XML external entity (XXE) attacks, or cause service disruptions through slow or malicious resources.

Technologies: [Xmlsoft Libxml2](https://junglewise.ai/threats/technologies/libxml2). Vendors: [Xmlsoft](https://junglewise.ai/threats/vendors/xmlsoft).

## Quick answers

**Is CVE-2026-86144 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-86144 being exploited in the wild.

**How severe is CVE-2026-86144?** Medium severity, with a CVSS score of 5.6, published 5 September 2026.

**Which products and versions are affected?** GNOME libxml2 before 2.15.4.

**Is there a fix for CVE-2026-86144?** A patch was published on 2026: Fix available in libxml2 2.15.4 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-86144 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-86144?** Check whether you run Xmlsoft Libxml2. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a missing security flag propagation issue in the xmlXIncludeProcess and xmlXIncludeProcessTree functions. These functions fail to pass the parseFlags parameter (which includes flags like XML_PARSE_NONET to disable network access) to included XML content, allowing an attacker to bypass intended security constraints. An application that sets parseFlags to restrict network access may still have those restrictions ignored when processing XInclude directives. This can enable XML External Entity (XXE) injection, Server-Side Request Forgery (SSRF), or denial-of-service attacks if the application uses a custom resource loader that accesses the network. The fix propagates parseFlags correctly during xinclude processing. Patch is available in libxml2 2.15.4 and later.

## Affected products

- GNOME libxml2 before 2.15.4

## Timeline

- 2026-09-05: disclosed
- 2026: patched: Fix available in libxml2 2.15.4

## References

- [https://github.com/GNOME/libxml2/commit/b63cd517afecb76582dd9488c55e54ceaf50de61](https://github.com/GNOME/libxml2/commit/b63cd517afecb76582dd9488c55e54ceaf50de61)
- [https://github.com/GNOME/libxml2/compare/v2.15.3...v2.15.4](https://github.com/GNOME/libxml2/compare/v2.15.3...v2.15.4)

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