CVE-2026-19857 Formidable Forms < 6.35 - Unauthenticated Arbitrary Shortcode Execution via [entry_key] Custom HTML Token
Unauthenticated attackers can execute arbitrary shortcodes via custom HTML tokens in Formidable Forms, potentially leading to server-side code execution.
- 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-2026-19857?
CVE-2026-19857 is a medium-severity code injection vulnerability in Unknown Formidable Forms, published on 16 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The Formidable Forms WordPress plugin before 6.35 does not prevent a request-derived value from reaching the WordPress shortcode parser when it substitutes a supported token into a form's custom HTML, allowing unauthenticated visitors to have arbitrary shortcodes, with attacker-chosen attributes, executed server-side on any page displaying an affected form.
Weakness: CWE-74
Which versions are affected by CVE-2026-19857?
How do I fix CVE-2026-19857?
No fix has been published for CVE-2026-19857 yet. Limit exposure of the affected software until one is available.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-19857 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-19857 exists.
Sources
Also known as GHSA-hgfq-v6h8-89x5.