How should we interpret CVSS severity scores?

CVSS estimates technical severity, but it does not automatically equal business risk. Prioritize using context like internet exposure, asset criticality, known exploitation, and whether compensating controls exist. A Medium CVSS on an exposed production system can be more urgent than a Critical on an isolated non-production host.

Vulnerability Database

Q: What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

Q: What's the difference between a vulnerability, an exploit, and a zero-day?

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. Risk increases sharply when exploitation becomes reliable or widespread.

Q: Why do vulnerabilities keep reappearing in our environment?

Recurring findings usually come from incomplete asset discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host.

Q: How do we prioritize remediation without burning out the team?

Use a repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress so remediation is steady, not reactive.

Q: How can SynScan help reduce vulnerability risk over time?

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.

361,925

Total vulnerabilities in the database

CVE-2026-54064 — nukeviet / nukeviet

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Summary

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(&#039;/^on/i&#039;, $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):

&lt;img src=&quot;x&quot; %0Conerror=&quot;alert(&#039;XSS&#039;)&quot;&gt;

Bypass 2 — Decimal HTML entity tab (`&#9;`) inside `javascript:` URI

unhtmlentities() strips the hex-encoded tab &#x09; via str_ireplace, but did not strip its decimal equivalent &#9;. 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&#9;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&amp;#9;ascript:alert(&#039;XSS&#039;))

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.

Patches

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('/&#0*(?:3[01]|[12][0-9]|[0-9]);/', '', $value);

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

Published: Jul 13, 2026
Updated: Jul 14, 2026
CVE: CVE-2026-54064
GHSA: GHSA-465g-4q99-5x86
Severity: High
Exploit:
CISA KEV:

CVSS v3:

Severity: High
Score: 8.7
AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

CWEs:

CWE-79

OWASP TOP 10:

A7 - Cross-Site Scripting (XSS)

Affected Software
References

Software	From	Fixed in
nukeviet / nukeviet	-	4.6.00

https://github.com/nukeviet/nukeviet/security/advisories/GHSA-465g-4q99-5x86

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Frequently Asked Questions

What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.