Netgate pfSense up to 2.9.0 WebGUI vpn_l2tp.php shared_secret injection

Summaryinfo

A vulnerability was found in Netgate pfSense up to 2.9.0 and classified as very critical. The affected element is an unknown function of the file vpn_l2tp.php of the component WebGUI. Executing a manipulation of the argument shared_secret can lead to injection. The identification of this vulnerability is CVE-2026-111221. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability has been found in Netgate pfSense up to 2.9.0 and classified as very critical. This vulnerability affects an unknown code of the file vpn_l2tp.php of the component WebGUI. The manipulation of the argument shared_secret with an unknown input leads to a injection vulnerability. The CWE definition for the vulnerability is CWE-74. The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

Netgate pfSense CE through 2.9.0 contains a configuration injection vulnerability that allows authenticated WebGUI users to inject mpd5 commands by submitting an unescaped RADIUS shared secret. Attackers with L2TP or PPPoE Server edit privileges can POST a secret containing a quote and newline to vpn_l2tp.php or services_pppoe_edit.php, appending an up-script that executes as root when a session starts.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-111221 since 10/15/2026. The exploitation appears to be easy. The attack can be initiated remotely. Additional levels of successful authentication are needed for exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 10/15/2026). The MITRE ATT&CK project declares the attack technique as T1055.

By approaching the search of inurl:vpn_l2tp.php it is possible to find vulnerable targets with Google Hacking.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• Firewall Software

Vendor

• Netgate

Name

• pfSense

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9.0

License

• open-source

CPE 2.3info

• 🔒
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CPE 2.2info

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Once again VulDB remains the best source for vulnerability data.

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