Summary
NukeViet: Multiple Anti-XSS Filter Bypasses Leading to Stored XSS in News Module
Two filter-bypass techniques in NukeViet\Core\Request::filterAttr() and NukeViet\Core\Request::unhtmlentities() allow a low-privileged user (any account with news post permission) to store and serve arbitrary JavaScript to any visitor of the affected page.
Affected Component
vendor/vinades/nukeviet/Core/Request.php, class NukeViet\Core\Request
Vulnerability Details
Bypass 1, Form Feed character prefix (\x0C) before event handler name
The filterAttr() method blocks event-handler attributes using:
preg_match('/^on/i', $attrSubSet[0])
PHP's trim() does not strip the ASCII Form Feed character (\x0C, U+000C). An attacker can prefix the attribute name with \x0C so that \x0Conerror does not match /^on/. The HTML5 browser parser treats \x0C as a valid whitespace separator and correctly activates the event handler.
Proof-of-concept payload (URL-encoded POST body field bodyhtml):
<img src="x" %0Conerror="alert('XSS')">
Bypass 2, Decimal HTML entity tab (	) inside javascript: URI
unhtmlentities() strips the hex-encoded tab 	 via str_ireplace, but did not strip its decimal equivalent 	. The keyword-blocking regex /j\s*a\s*v\s*a\s*s\s*c\s*r\s*i\s*p\s*t/si uses \s* which does not match HTML entities. The value jav	ascript:alert() passes the filter, is stored in the database, and is decoded by the browser into a working javascript: URI.
Proof-of-concept payload (inside a Markdown-style link):
[Click me](jav	ascript:alert('XSS'))
Workarounds
None. Update to the patched version.
Resources
- CWE-79: Improper Neutralization of Input During Web Page Generation (Cross-site Scripting)
- OWASP WSTG-INPV-02: Testing for Stored Cross Site Scripting
- OWASP Top 10 A03:2021 – Injection
Impact
An authenticated attacker with news-posting permission can inject persistent JavaScript that executes in the browser of any user (including administrators) who views the affected article. This enables session cookie theft, credential harvesting, defacement, and further privilege escalation.
Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.
CVE-2026-54064 has a CVSS score of 8.7 (High). The vector is network-reachable, low privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (4.6.00); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Fixed in commit <commit-sha> by modifying vendor/vinades/nukeviet/Core/Request.php:
filterAttr(), strip all ASCII control characters (\x00–\x20) from the attribute name before the/^on/check:$attrSubSet[0] = preg_replace('/[\x00-\x20]/', '', strtolower($attrSubSet[0]));unhtmlentities(), strip decimal HTML entities for all ASCII control characters (0–31) before the keyword checks:$value = preg_replace('/�*(?:3[01]|[12][0-9]|[0-9]);/', '', $value);
Frequently Asked Questions
- What is CVE-2026-54064? CVE-2026-54064 is a high-severity cross-site scripting (XSS) vulnerability in nukeviet/nukeviet (composer), affecting versions < 4.6.00. It is fixed in 4.6.00. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
- How severe is CVE-2026-54064? CVE-2026-54064 has a CVSS score of 8.7 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of nukeviet/nukeviet are affected by CVE-2026-54064? nukeviet/nukeviet (composer) versions < 4.6.00 is affected.
- Is there a fix for CVE-2026-54064? Yes. CVE-2026-54064 is fixed in 4.6.00. Upgrade to this version or later.
- Is CVE-2026-54064 exploitable, and should I be worried? Whether CVE-2026-54064 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-54064 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-54064? Upgrade
nukeviet/nukevietto 4.6.00 or later.