# CVE-2026-57438: Nokogiri use-after-free in XInclude processing

Source: https://junglewise.ai/threats/cve-2026-57438-nokogiri-use-after-free-in-xinclude-processing  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-25. Updated: 2026-06-25  
License: CC BY 4.0 with a link back

CVE-2026-57438 · Severity: info · CVSS 2.2 · Published 2026-06-25

Nokogiri is a widely used Ruby library for processing XML and HTML documents. A technical flaw in how it handles specific document inclusions could allow a program to crash or behave unpredictably by accessing memory that has already been cleared. This issue primarily affects applications using specific, non-standard processing sequences and is resolved by updating the library.

Technologies: [nokogiri (RubyGems)](https://junglewise.ai/threats/technologies/nokogiri). Vendors: [RubyGems](https://junglewise.ai/threats/vendors/rubygems).

## Quick answers

**Is CVE-2026-57438 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-57438 being exploited in the wild.

**How severe is CVE-2026-57438?** Informational severity, with a CVSS score of 2.2, published 25 June 2026.

**Which products and versions are affected?** nokogiri (RubyGems) ECOSYSTEM:introduced=0,fixed=1.19.4.

**Is there a fix for CVE-2026-57438?** Yes. nokogiri (RubyGems): upgrade to 1.19.4 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-57438 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-57438?** Check whether you run nokogiri (RubyGems) at an affected version. 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.

## How to fix

- nokogiri (RubyGems): upgrade to 1.19.4 or later

  ```sh
  bundle update nokogiri
  ```


## Technical details

A use-after-free (CWE-416) vulnerability exists in the CRuby implementation of Nokogiri's XInclude processing. When `Nokogiri::XML::Node#do_xinclude` is called, it replaces `<xi:include>` nodes in place and frees the original nodes and their descendants. If the application has already referenced these nodes in Ruby, the Ruby objects remain linked to the now-freed memory, leading to invalid memory reads or writes. This requires a specific execution flow where a document is parsed without XInclude, traversed to expose nodes to Ruby, and then subsequently processed for XInclude. The issue is fixed in version 1.19.4 by performing substitutions on defensive copies.

## Affected products

- sparklemotion Nokogiri < 1.19.4

## Identifiers

- CVE-2026-57438
- GHSA-wfpw-mmfh-qq69

## Timeline

- 2026-06-18: advisory: GitHub advisory published by maintainers
- 2026-06-25: disclosed: CVE published to NVD
- 2026-06-25: patched: Fixed in version 1.19.4

## References

- [https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-wfpw-mmfh-qq69](https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-wfpw-mmfh-qq69)

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- [Nokogiri unchecked return value in canonicalize method](https://junglewise.ai/threats/nokogiri-unchecked-return-value-in-canonicalize-method-3863de91)
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