What is CVE-2026-57436?

CVE-2026-57436 is a medium-severity vulnerability in Nokogiri, classified under Use After Free. CVSS score: 5.3/10. Published 2026-06-25.

How severe is CVE-2026-57436?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Use After Free in Nokogiri

CVE-2026-57436

Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, Nokogiri::XML::Document#root= validated only that the new root was a Nokogiri::XML::Node, allowing a DTD node to be set as the document roo…

Vulnerability class: Use-After-Free

EPSS: 0.003 (24.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

Affected products

Nokogiri
Sparklemotion Nokogiri — versions < 1.19.4

Weakness classification (CWE)

CWE-416 — Use After Free

References

security-advisories@github.com (x_refsource_CONFIRM, Mitigation, Vendor Advisory)

Frequently asked questions

What is CVE-2026-57436?: CVE-2026-57436 is a medium-severity vulnerability in Nokogiri, classified under Use After Free. CVSS score: 5.3/10. Published 2026-06-25.
How severe is CVE-2026-57436?: Medium severity. CVSS v3 base score is 5.3 out of 10.