CVE-2026-111217 Netgate CVE debrief

Who should care

Defenders responsible for pfSense CE instances, especially those with untrusted or internet-exposed management interfaces, should assess exposure and prioritize remediation. System administrators and security teams managing Virtual IP configurations and CARP status should verify the integrity of their configurations and monitor for potential exploitation attempts.

Why it matters

CVE-2026-111217 is a high-severity OS command injection vulnerability in Netgate pfSense CE through version 2.9.0. Authenticated users with Virtual IP edit privileges can execute commands as root by storing a malicious CARP VHID. Defenders should prioritize verifying exposure, remediating vulnerable instances, and implementing input validation and sanitization for CARP VHID.

• Potential for authenticated users to execute commands as root
• Possible exploitation via unvalidated CARP VHID
• Required verification of pfSense CE version and Virtual IP configurations
• Need for input validation and sanitization of CARP VHID

Technical summary

The vulnerability exists in the pfSense CE software, specifically in the handling of CARP VHID. An authenticated user with Virtual IP edit privileges can store a malicious VHID containing shell metacharacters, which can be executed as root when processed by interface_ipalias_configure() ifconfig calls or get_carp_interface_status() during CARP status rendering. This vulnerability allows for potential command injection and exploitation, emphasizing the need for input validation and sanitization of CARP VHID, as well as restricting Virtual IP edit privileges to trusted users.

Defensive priority

Defenders should prioritize verifying exposure and remediating vulnerable pfSense CE instances, especially those with untrusted or internet-exposed management interfaces.

Recommended defensive actions

• Verify pfSense CE version and check for Virtual IP edit privileges exposure
• Restrict Virtual IP edit privileges to trusted users
• Implement input validation and sanitization for CARP VHID
• Monitor for suspicious activity and potential exploitation attempts
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, but the scope of affected versions and potential exploitation remains limited. Official sources indicate that the vulnerability exists in pfSense CE through version 2.9.0.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.