CVE-2026-57436
Nokogiri: Possible Use-After-Free when setting `Document#root=` to an invalid node type
EPSS 0.31%
Description
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 root. The result is a heap use-after-free during garbage collection or finalization, leading to an invalid memory read or potentially a segfault. This vulnerability is fixed in 1.19.4.
How to fix CVE-2026-57436
To remediate CVE-2026-57436, upgrade the affected package to a fixed version below.
- —upgrade to 1.19.4 or later
Is CVE-2026-57436 being exploited?
Low — EPSS is 0.3%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 1.19.4
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U |