CVE-2026-57437: Nokogiri: Possible Use-After-Free when directly using `NokogirI::XML::XPathContext` beyond document lifetime

mediumCVSS 5.3CVE-2026-57437

CSIRTS triage

vendor: Nokogiri product: NokogiriOther

What: A possible use-after-free vulnerability occurs when using Nokogiri::XML::XPathContext beyond the document's lifetime.
Who is affected: Deployments using Nokogiri are affected.
Urgency: Remediation is necessary due to the medium severity of the vulnerability.
Action: Update to the latest version of Nokogiri.

AI-assisted analysis generated from the source advisory — verify against the original.

⚡ Watch Nokogiri

Get an email when a new Nokogiri advisory drops — max one per day, one-click unsubscribe.

Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 5.3
Published: 2026-06-09
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-57437

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-574370.31% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 23% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-57437	coverage & exploitation status	NVD · CVE.org

Recent advisories for Nokogiri

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

highCVE-2026-57435: Nokogiri: Possible Use-After-Free when setting an attribute value via `Nokogiri::XML::Attr#val…msrc · 2026-06-09
mediumCVE-2026-57436: Nokogiri: Possible Use-After-Free when setting `Document#root=` to an invalid node typemsrc · 2026-06-09
mediumCVE-2026-57438: Nokogiri: Possible Use-After-Free in XInclude Processingmsrc · 2026-06-09
highCVE-2026-57236: Nokogiri: Possible Use-After-Free when `Nokogiri::XML::Document#encoding=` raises an exceptionmsrc · 2026-06-09
lowCVE-2026-57234: Nokogiri: XML::Schema on JRuby allows network requests when NONET is set, bypassing CVE-2020-2…msrc · 2026-06-09
highCVE-2026-57434: Nokogiri: Null Pointer Dereference calling methods on uninitialized wrapper classesmsrc · 2026-06-09