CVE-2020-26247: XXE in Nokogiri

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-12-30 · updated 2026-06-17
Weakness: CWE-611

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.

Affected products

Debian Linux: 9.0, 10.0
sparklemotion nokogiri: before 1.11.0; 1.11.0-rc1, 1.11.0-rc2, 1.11.0-rc3 — fixed in 1.11.0
Rubygems Nokogiri: before 1.11.0; 1.0.0, 1.0.1, 1.0.2, 1.0.3, 1.0.4, 1.0.5 (+118) — fixed in 1.11.0

How to fix

Upgrade to a fixed version: sparklemotion nokogiri 1.11.0; Rubygems Nokogiri 1.11.0. Check the vendor advisory for mitigations.

References

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