CVE-2026-4281 Missing authorization in FormLift for Infusionsoft Web Forms
Unauthenticated attackers can hijack the Infusionsoft connection by exploiting missing authorization checks in the OAuth flow, redirecting API traffic to attacker servers.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-4281?
CVE-2026-4281 is a medium-severity missing authorization vulnerability in trainingbusinesspros FormLift for Infusionsoft Web Forms, published on 26 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-862
Which versions are affected by CVE-2026-4281?
How do I fix CVE-2026-4281?
No fix has been published for CVE-2026-4281 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-4281 being exploited?
There is no known exploitation of CVE-2026-4281 in the wild and no public exploit code.
Sources
Also known as GHSA-5rfm-3pqq-3xm3.