Nokogiri is an open source XML and HTML library for the Ruby programming language. From 1.12.0 until 1.19.5, the C extension on CRuby and TruffleRuby has a Nokogiri::HTML5 serializer that does not escape text inside noscript elements or angle brackets inside attribute values. When an application sanitizes untrusted HTML with the default parsing options, allows noscript, and sends serialized output to a scripting-enabled browser, the browser can parse markup that Nokogiri did not produce, enabling mutation cross-site scripting. Using parse_noscript_content_as_text: true is the recommended workaround, not the vulnerable default. JRuby is not affected because it does not implement Nokogiri::HTML5. This issue is fixed in version 1.19.5.
Metrics
Affected Vendors & Products
Advisories
| Source | ID | Title |
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Github GHSA |
GHSA-4p39-36wj-23h4 | Nokogiri: Mutation XSS through `noscript` content in Nokogiri's HTML5 serializer |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Tue, 10 Nov 2026 20:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Nokogiri is an open source XML and HTML library for the Ruby programming language. From 1.12.0 until 1.19.5, the C extension on CRuby and TruffleRuby has a Nokogiri::HTML5 serializer that does not escape text inside noscript elements or angle brackets inside attribute values. When an application sanitizes untrusted HTML with the default parsing options, allows noscript, and sends serialized output to a scripting-enabled browser, the browser can parse markup that Nokogiri did not produce, enabling mutation cross-site scripting. Using parse_noscript_content_as_text: true is the recommended workaround, not the vulnerable default. JRuby is not affected because it does not implement Nokogiri::HTML5. This issue is fixed in version 1.19.5. | |
| Title | Nokogiri: Mutation XSS through `noscript` content in Nokogiri's HTML5 serializer | |
| Weaknesses | CWE-116 CWE-79 |
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| References |
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| Metrics |
cvssV4_0
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Projects
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-11-10T20:14:40.408Z
Reserved: 2026-11-10T17:07:43.283Z
Link: CVE-2026-126063
No data.
Status : Received
Published: 2026-11-10T21:19:23.990
Modified: 2026-11-10T21:19:23.990
Link: CVE-2026-126063
No data.
OpenCVE Enrichment
No data.
Github GHSA