NokogiriApplication
CVE-2026-57235
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::NodeSet#[] (and its alias #slice) checked the requested index against the node set's bounds using a 32-bit-truncated copy of the index. A large negative index could pass the check and then be used at full width, reading outside the node set's storage. On CRuby this is an out-of-bounds read that typically crashes the process; on JRuby it is not memory-unsafe but returns an incorrect node. 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 confidenceIn Nokogiri prior to 1.19.4, the NodeSet#[] and #slice methods performed bounds checking using a 32-bit-truncated copy of the requested index. A large negative index could pass this bounds check when truncated but then be used at full width, causing an out-of-bounds read beyond the node set's storage allocation. On CRuby this manifests as a process crash; on JRuby it returns incorrect nodes without memory unsafety.
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
- Low
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
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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Identify if Nokogiri is installedRun 'gem list nokogiri' or check Gemfile.lock for the nokogiri entryAffected if Nokogiri is not present in the environment, the vulnerability does not apply
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Determine installed Nokogiri versionRun 'gem list nokogiri --remote' or inspect the version field in Gemfile.lockAffected if Unable to determine the version, manual inspection of the gem version may be required
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Compare version against affected rangeCheck if the installed version is less than 1.19.4 (e.g., 1.19.3, 1.18.x, 1.16.x, etc.)Affected if Version is < 1.19.4, the environment is running a vulnerable version
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Identify use of vulnerable NodeSet methodsSearch codebase for calls to NodeSet#[] or NodeSet#slice methods, especially with dynamic or user-controlled index argumentsAffected if Code uses these methods with large negative indices that could trigger the bounds check bypass
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Test bounds check behavior (optional verification)Create a Nokogiri::XML::NodeSet with a small number of nodes and attempt to access with a large negative index (e.g., nodes[-2147483648] or smaller)Affected if Accessing beyond the node set storage allocation causes a crash (CRuby) or returns incorrect nodes (JRuby), confirming the vulnerability is present
The environment is affected if Nokogiri version is below 1.19.4 and code uses NodeSet#[] or NodeSet#slice with large negative indices.
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 to remediate this vulnerability.
1.19.4
- Identify your project dependency management tool (Bundler for Gemfile, or direct gem installation)
- If using Bundler, open your Gemfile and locate the nokogiri dependency line
- Update the nokogiri version constraint to require version 1.19.4 or later (e.g., gem 'nokogiri', '>= 1.19.4')
- Run `bundle update nokogiri` to update the gem to the specified version
- Verify the installed version by running `gem list nokogiri` or checking in your Ruby environment
- Test your application to ensure the upgrade does not break existing functionality
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Nokogiri
Scoped from the published advisory
- Consultation1.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,376.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-57235 — 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-2026-57235 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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