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.

352,262

Total vulnerabilities in the database

CVE-2026-49279 — wwbn / avideo

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

AVideo: Stored XSS via `autoEvalCodeOnHTML` in MessageSQLite WebSocket Handler

Summary

AVideo has a stored XSS vulnerability in the WebSocket messaging system. The MessageSQLite.php handler only strips autoEvalCodeOnHTML from $json['msg'], but msgToResourceId() reads from $msg['json'] with higher priority. An attacker can place the XSS payload in the json key instead of msg, bypassing the sanitization entirely.

Affected Versions

AVideo <= latest

Vulnerability Details

Root Cause: Shallow sanitization only covers `$json['msg']`

plugin/YPTSocket/MessageSQLite.php lines 268-271 — the incomplete fix:

if (empty($msgObj-&gt;isCommandLineInterface) &amp;&amp; ($msgObj-&gt;sentFrom ?? &#039;&#039;) !== &#039;php&#039;) {
    if (is_array($json[&#039;msg&#039;] ?? null)) {
        unset($json[&#039;msg&#039;][&#039;autoEvalCodeOnHTML&#039;]);  // Only strips from $json[&#039;msg&#039;]
    }
}

plugin/YPTSocket/MessageSQLite.php lines 361-367 — the bypass via msgToResourceId():

if (!empty($msg[&#039;json&#039;])) {
    $obj[&#039;msg&#039;] = $msg[&#039;json&#039;];       // $msg[&#039;json&#039;][&#039;autoEvalCodeOnHTML&#039;] is NEVER stripped
} else if (!empty($msg[&#039;msg&#039;])) {
    $obj[&#039;msg&#039;] = $msg[&#039;msg&#039;];        // Only this path was sanitized
} else {
    $obj[&#039;msg&#039;] = $msg;
}

Compare with the correctly patched Message.php (lines 254-256):

$json = removeAutoEvalCodeOnHTMLRecursive($json);  // Strips from ALL nested paths

And MessageSQLiteV2.php (lines 302-303):

$json = removeAutoEvalCodeOnHTMLRecursive($json);  // Same recursive fix

MessageSQLite.php does not call removeAutoEvalCodeOnHTMLRecursive() at all.

Attack Chain

Attacker sends a WebSocket message with autoEvalCodeOnHTML in the json key instead of msg
The fix at line 268-271 only checks $json['msg'] — the json key is untouched
msgToResourceId() reads $msg['json'] first (line 361) because !empty($msg['json']) is true
The payload is delivered to the victim's WebSocket client and evaluated via autoEvalCodeOnHTML

Proof of Concept

// Connect to AVideo WebSocket as authenticated user
const ws = new WebSocket(&#039;wss://TARGET/plugin/YPTSocket/server.php?token=USER_TOKEN&#039;);

ws.onopen = () =&gt; {
  ws.send(JSON.stringify({
    msg: &quot;Hello&quot;,                               // sanitized path — decoy
    json: {autoEvalCodeOnHTML: &quot;alert(&#039;XSS&#039;)&quot;},  // unsanitized path — payload
    to_users_id: VICTIM_USER_ID,
    resourceId: RESOURCE_ID
  }));
};
// Victim&#039;s client evaluates alert(&#039;XSS&#039;) via autoEvalCodeOnHTML mechanism

Impact

An authenticated attacker can:

Execute arbitrary JavaScript in any connected user's browser session via the WebSocket messaging system
Steal session cookies and authentication tokens
Perform account takeover via session hijacking
Chain with CSRF to execute admin actions on behalf of the victim

The vulnerability affects the default SQLite WebSocket backend configuration.

Suggested Remediation

Apply removeAutoEvalCodeOnHTMLRecursive() in MessageSQLite.php, consistent with Message.php and MessageSQLiteV2.php:

// Before (vulnerable — shallow strip):
if (is_array($json[&#039;msg&#039;] ?? null)) {
    unset($json[&#039;msg&#039;][&#039;autoEvalCodeOnHTML&#039;]);
}

// After (fixed — recursive strip):
$json = removeAutoEvalCodeOnHTMLRecursive($json);

Published: Jun 4, 2026
Updated: Jun 5, 2026
CVE: CVE-2026-49279
GHSA: GHSA-2fhx-q92v-5fhv
Severity: High
Exploit:
CISA KEV:

No technical information available.

CWEs:

CWE-79

OWASP TOP 10:

A7 - Cross-Site Scripting (XSS)

Affected Software
References

Software	From	Fixed in
wwbn / avideo	-	29.0.x

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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.