CVE-2026-104828
7.2HighPublished 15 Oct 2026 · NVD status: Deferred · AI triage by gemini-3.8-flash
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Impact
- Limited impact
- Weakness
- CWE-79
Impact
Remote attackers can execute cross-site scripting (XSS) in users' browsers by passing encoded payloads into applications using this library for HTML sanitization or serialization. No authentication or special access is required.
Root cause
HTMLWriterFilter decodes character entities within TEXTAREA and TITLE elements during parsing but fails to re-encode them when serializing, emitting raw markup instead.
Affected systems
HtmlUnit Neko prior to version 5.4.0
CVSS v3.1 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Fix & remediation
Upgrade htmlunit-neko dependency to version 5.4.0. If you cannot patch immediately, strip or manually escape TEXTAREA and TITLE tag contents before serialization.
$ mvn dependency:tree | grep htmlunit-nekoAI-suggested. Run it in staging first and check it against the vendor advisory. Why?
NVD description
HtmlUnit Neko is an HtmlUnit adaptation of NekoHTML. Prior to 5.4.0, HTMLWriterFilter writes decoded TEXTAREA and TITLE character content without entity encoding because both elements are treated as special content. During a parse-and-serialize round trip, entity references inside these escapable raw-text elements are decoded by the parser and then emitted as raw markup by printCharacters(), changing the document's semantics. Applications that use htmlunit-neko in an HTML sanitizer, content filter, or other parse-transform-serialize pipeline can therefore turn attacker-controlled encoded text into executable markup when the output is rendered by a browser. This issue is fixed in version 5.4.0.