Nokogiri
CVE-2021-41098
HIGH
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A02:2025 - Security Misconfiguration
ASVS 5.0
V13 - Configuration XML external entity prevention
MITRE ATT&CK
2 techniques across 2 tactics: Initial Access, Collection The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. |
| Exploit ScenarioDerived | A remote attacker could read arbitrary files or perform SSRF through XML processing by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability. |
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Alert meAnalysisAI
Nokogiri is a Rubygem providing HTML, XML, SAX, and Reader parsers with XPath and CSS selector support. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This XML External Entity (XXE) vulnerability could allow attackers to read arbitrary files or perform SSRF through XML processing.
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Disable external entity processing in XML parsers, use JSON instead of XML where possible.
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in rubygems
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as XML External Entity (XXE) (CWE-611), which allows attackers to read arbitrary files or perform SSRF through XML processing. Nokogiri is a Rubygem providing HTML, XML, SAX, and Reader parsers with XPath and CSS selector support. In Nokogiri v1.12.4 and earlier, on JRuby only, the SAX parser resolves external entities by default. Users of Nokogiri on JRuby who parse untrusted documents using any of these classes are affected: Nokogiri::XML::SAX::Parse, Nokogiri::HTML4::SAX::Parser or its alias Nokogiri::HTML::SAX::Parser, Nokogiri::XML::SAX::PushParser, and Nokogiri::HTML4::SAX::PushParser or its alias Nokogiri::HTML::SAX::PushParser. JRuby users should upgrade to Nokogiri v1.12.5 or later to receive a patch for this issue. There are no workarounds available for v1.12.4 or earlier. CRuby users are not affected. Affected products include: Nokogiri.
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
Nokogiri is a Rubygem providing HTML, XML, SAX, and Reader parsers with XPath and CSS selector support. In Nokogiri v1.12.4 and earlier, on JRuby only, the SAX parser resolves external entities by default. Users of Nokogiri on JRuby who parse untrusted documents using any of these classes are affected: Nokogiri::XML::SAX::Parse, Nokogiri::HTML4::SAX::Parser or its alias Nokogiri::HTML::SAX::Parser, Nokogiri::XML::SAX::PushParser, and Nokogiri::HTML4::SAX::PushParser or its alias Nokogiri::HTML::SAX::PushParser. JRuby users should upgrade to Nokogiri v1.12.5 or later to receive a patch for this issue. There are no workarounds available for v1.12.4 or earlier. CRuby users are not affected.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
XML External Entity (XXE) attacks exploit XML parsers that process Document Type Definitions (DTDs) without proper restrictions.
Affected Products (CPE)NVD
Nokogiri is an open source XML and HTML library for Ruby. Rated high severity (CVSS 8.2), this vulnerability is remotely
A command injection vulnerability in Nokogiri v1.10.3 and earlier allows commands to be executed in a subprocess via Rub
Denial-of-service in Nokogiri before 1.19.3 stems from three distinct ReDoS vulnerabilities in the CSS selector tokenize
Out-of-bounds memory read in Nokogiri (CRuby) versions before 1.19.4 crashes the host Ruby process when application code
Nokogiri is an open source XML and HTML library for the Ruby programming language. Rated high severity (CVSS 7.5), this
Nokogiri is an open source XML and HTML library for Ruby. Rated high severity (CVSS 7.5), this vulnerability is remotely
Heap memory leaks in Nokogiri's XSLT transform method (versions before 1.19.3) enable gradual denial of service against
Unchecked return value in Nokogiri's CRuby extension (versions 1.5.1 through 1.19.0) causes the `canonicalize` method to
Out-of-bounds read in Nokogiri's `NodeSet#[]` method (all versions before 1.19.4) enables an attacker who can supply a l
Nokogiri is a Rubygem providing HTML, XML, SAX, and Reader parsers with XPath and CSS selector support. Rated medium sev
NONET network restriction bypass in Nokogiri's JRuby implementation permits external resource fetching during XML Schema
Use-after-free in Nokogiri's CRuby XInclude processing (versions prior to 1.19.4) can leave Ruby wrapper objects pointin
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