CVE intelligence

CVE-2026-57236

Vulnerability intelligence

Published Jun 25, 2026Sources checked Nov 12, 2026

8.2HIGHCVSS out of 10

What this means

Review the available evidence

CVE-2026-57236 and is rated High severity with a CVSS score of 8.2. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Jun 30, 2026

CBL-Mariner Releases

Vendor-listed releases

1.19.4-1

CISA KEVNot listedBased on the latest collected catalog

EPSS0.4%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-57236?

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.

Source: NVD