CVE-2026-57236: Nokogiri

High severity, CVSS 8.2. EPSS: 0.4% chance of exploitation in the next 30 days.

Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, calling Document#encoding= with an invalid encoding (e.g., a non-string, or a string containing a null byte) raises an exception, but only after freeing the document's current encoding string without replacing it. The document is left referencing freed memory, so the next call to Document#encoding reads invalid memory, which can cause a segfault or leak freed bytes into a Ruby String. Affects the CRuby (libxml2) implementation only; JRuby is not affected. This vulnerability is fixed in 1.19.4.

Affected products

• Nokogiri Nokogiri: before 1.19.4 (fixed in 1.19.4)

Published 2026-06-25. Last modified 2026-06-26.