FormLift for Infusionsoft Web Forms <= 7.5.21 - Missing Authorization to Unauthenticated Infusionsoft Connection Hijack via OAuth Connection Flow
Strategic Overview
- Status
- Patched in 7.5.22
- Affected Plugin
- FormLift for Keap (Legacy) Web Forms
- Affected Version
<= 7.5.21- CVSS
- 5.3Medium
- Weakness type
- CWE-862 · Missing Authorization
- CVE
CVE-2026-4281
At a glance
CVE-2026-4281 is a medium-severity Missing Authorization vulnerability in the FormLift for Keap (Legacy) Web Forms WordPress plugin, affecting versions <= 7.5.21. It carries a CVSS score of 5.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 7.5.22; sites on affected versions should update now. Disclosed March 2026, reported by Nabil Irawan.
Vulnerability Overview
The FormLift for Infusionsoft Web Forms plugin for WordPress is vulnerable to Missing Authorization in all versions up to, and including, 7.5.21. This is due to missing capability checks on the connect() and listen_for_tokens() methods of the FormLift_Infusionsoft_Manager class, both of which are hooked to 'plugins_loaded' and execute on every page load. The connect() function generates an OAuth connection password and leaks it in the redirect Location header without verifying the requesting user is authenticated or authorized. The listen_for_tokens() function only validates the temporary password but performs no user authentication before calling update_option() to save attacker-controlled OAuth tokens and app domain. This makes it possible for unauthenticated attackers to hijack the site's Infusionsoft connection by first triggering the OAuth flow to obtain the temporary password, then using that password to set arbitrary OAuth tokens and app domain via update_option(), effectively redirecting the plugin's API communication to an attacker-controlled server.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user.
CWE-862: Missing Authorization
FormLift for Keap (Legacy) Web Forms <= 7.5.21 carries this weakness at plugins_loaded, and reaching it takes no account at all. A missing authorization check means a function is reachable by anyone who can reach the endpoint, because the code never asks whether the caller is allowed to perform the action.
Any user who can reach the endpoint gets to run an action reserved for higher-privileged roles, from reading protected data to changing settings or content. For FormLift for Keap (Legacy) Web Forms the fix is 7.5.22: builds <= 7.5.21 are affected, anything from 7.5.22 onward is not.
Remediation
Update to version 7.5.22, or a newer patched version
How does WordSec protect against this?
This one needs no account at all, which puts it outside what login hardening can reach; WordSec's login security narrows the account-level paths around it, and the firewall is what inspects the request itself. None of that substitutes for the fix: FormLift for Keap (Legacy) Web Forms 7.5.22 closes this, and updating the plugin is the step that ends it.
- Login Security
- Alerts
External References
Related records
Other vulnerabilities in FormLift for Keap (Legacy) Web Forms
Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C