NokogiriApplication
CVE-2026-57437
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedNokogiri 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceNokogiri::XML::XPathContext does not keep its source document alive for garbage collection. If an XPathContext outlives its document and the document gets collected, evaluating an XPath expression can read invalid memory and potentially segfault due to a use-after-free condition.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
NokogiriApplication
< 1.19.4CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check installed Nokogiri versionRun `gem list nokogiri` or in Ruby: `require 'nokogiri'; puts Nokogiri::VERSION`Affected if Version is below 1.19.4
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Identify XPathContext usage in codebaseSearch source code for 'XPathContext' or 'XPathContext.new' patternsAffected if XPathContext is instantiated in any Ruby files
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Check for document lifecycle patternsReview code where documents may be garbage collected while XPathContext references to them might still existAffected if Code creates XPathContext objects that could persist after their source document goes out of scope
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Verify runtime Ruby versionRun `ruby --version`Affected if Not directly relevant to CVE but needed for full environment context
You are affected if using Nokogiri version below 1.19.4 AND your code creates XPathContext instances that may outlive their source documents, enabling the use-after-free condition when XPath expressions are evaluated after garbage collection.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped1.19.4
Upgrade Nokogiri to version 1.19.4 or later. Avoid directly constructing XPathContext objects that may outlive their source documents.
Nokogiri 1.19.4
- Run `gem install nokogiri` or add `gem 'nokogiri', '~> 1.19.4'` to your Gemfile
- Run `bundle update nokogiri` to update the dependency in your project
- Verify the upgrade was successful by running `ruby -e "require 'nokogiri'; puts Nokogiri::VERSION"` and confirming it shows 1.19.4 or later
- If using a Gemfile.lock, commit the updated lockfile to ensure consistent deployments
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Nokogiri
Scoped from the published advisory
- Consultation1.0 h
- Implementation0.5 h
- Testing1.0 h
- Review / QA0.5 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-57437 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-57437 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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