Executive brief
Nokogiri is a widely used Ruby library for processing XML and HTML data. A technical flaw in how the library handles uninitialized objects can lead to a program crash (denial of service). This issue is considered low risk because it requires a specific programming error in the application code rather than being triggered by malicious user input.
Technical details
A NULL pointer dereference exists in Nokogiri's native wrapper classes inheriting from Nokogiri::XML::Node. The vulnerability is triggered when application code calls .allocate directly on a native-backed class and subsequently invokes methods on the resulting uninitialized object before proper initialization. This results in a crash of the Ruby process. The issue is limited to CRuby implementations; JRuby is not affected. A fix is available in version 1.19.4, which adds checks for missing native data pointers and raises a RuntimeError instead of crashing.
Affected products
- sparklemotion Nokogiri < 1.19.4
Timeline
- 2026-06-18: advisory: GitHub Security Advisory published by maintainers
- 2026-06-25: disclosed: CVE published to NVD