CVE-2026-57437
Nokogiri: Possible Use-After-Free when directly using `NokogirI::XML::XPathContext` beyond document lifetime
Description
Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, Nokogiri::XML::XPathContext did not keep its source document alive for garbage collection. If an XPathContext outlived its document and the document was collected, evaluating an XPath expression could read invalid memory and potentially segfault. This is only reachable when application code constructs an XPathContext directly and lets the document become unreachable while continuing to use the context. The normal Document#xpath, #css, and related search methods are not affected, and it is not triggerable by malicious document input. This vulnerability is fixed in 1.19.4.
How to fix CVE-2026-57437
To remediate CVE-2026-57437, upgrade the affected package to a fixed version below.
- —upgrade to 1.19.4 or later
Is CVE-2026-57437 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/U:Clear |