---
id: GHSA-p67v-3w7g-wjg7
title: >-
  Nokogiri: Possible Use-After-Free when directly using
  `NokogirI::XML::XPathContext` beyond document lifetime
summary: >-
  Nokogiri: Possible Use-After-Free when directly using
  `NokogirI::XML::XPathContext` beyond document lifetime
severity: low
cwe:
  - CWE-416
vendor: nokogiri
product: nokogiri
affected:
  - nokogiri < 1.19.4
patched:
  - nokogiri 1.19.4
published: '2026-06-19'
updated: '2026-06-19'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-p67v-3w7g-wjg7'
references:
  - url: >-
      https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-p67v-3w7g-wjg7
  - url: 'https://github.com/advisories/GHSA-p67v-3w7g-wjg7'
tags:
  - ghsa
  - rubygems
ingestedAt: '2026-06-22T15:52:21.089Z'
ecosystem: rubygems
---

## Overview

### Summary

`Nokogiri::XML::XPathContext` did not keep its source document alive for garbage collection. If an `XPathContext` outlived its document and the document was collected, evaluating an XPath expression could read invalid memory and potentially segfault.

This is only reachable when application code constructs an `XPathContext` directly and lets the document become unreachable while continuing to use the context. The normal `Document#xpath`, `#css`, and related search methods are not affected, and it is not triggerable by malicious document input.

Nokogiri 1.19.4 makes `XPathContext` keep its source document alive for as long as the context exists.

Only the CRuby implementation is affected. JRuby is not affected.

### Severity

The Nokogiri maintainers have evaluated this as low severity. Reaching it requires an unusual API-usage pattern that does not arise during normal use. The application must construct an `XML::XPathContext` directly and continue using it after allowing its source document to be garbage-collected. Nokogiri 1.19.4 makes this pattern safe with no change to the public API. The context now keeps its source document alive for as long as it exists.

### Mitigation

Upgrade to Nokogiri 1.19.4 or later.

As a workaround, ensure the source document remains referenced for as long as any `XPathContext` created from it is in use. The standard `Document#xpath`, `#css`, and related search methods already do this and are unaffected.

### Credit

This issue was responsibly reported by Zheng Yu from depthfirst.com.

## Affected packages

- `nokogiri < 1.19.4`

## Remediation

Upgrade to a patched release:

- `nokogiri 1.19.4`