Is there a public exploit for CVE-2026-126063?

No public exploit for CVE-2026-126063 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-126063?

CVE-2026-126063 scores CVSS 2.3 (v4.0), rated low. EPSS puts the chance of exploitation in the next 30 days at 0.00561%.

What does CVE-2026-126063 affect?

CVE-2026-126063 affects nokogiri.

2.3 Low

Nokogiri: Mutation XSS through `noscript` content in Nokogiri's HTML5 serializer

CVE-2026-126063

Summary Nokogiri's HTML5 serializer did not escape text inside noscript elements, or inside attribute values. When a document parsed with the default options is serialized, a browser with scripting enabled can parse the output into markup that Nokogiri's parser never produced. This is a mutation XSS for applications that sanitize untrusted HTML with Nokogiri::HTML5, allow noscript elements, and send the serialized output to browsers. Nokogiri 1.19.5 escapes both, as the HTML standard's serialization algorithm requires. Text inside noscript is still emitted unescaped for documents parsed with parsenoscriptcontentastext: true. Only the C extension (CRuby and TruffleRuby) is affected. JRuby does not implement Nokogiri::HTML5. Severity The Nokogiri maintainers have evaluated this as low severity (CVSS 2.3, CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N). Exploitation requires an application that allows noscript in sanitized HTML. Loofah and rails-html-sanitizer do not allow it by default, and Sanitize always removes it. Mitigation Upgrade to Nokogiri 1.19.5 or later. Applications that sanitize HTML and allow noscript should parse with parsenoscriptcontentastext: true…

Assessment

CVSS: 2.3 (v4.0)
Severity: Low
EPSS: 0.00561% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 10 November 2026
Last updated: 10 November 2026
Affected: nokogiri
Weakness: CWE-116, CWE-79

CVSS vectorCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

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