Vulnerability · Published Sep 4, 2026 · Assigned by VulnCheck
CVE-2026-85602Grav Form Plugin before 9.1.20 reCAPTCHA v3 Authentication Bypass
Medium 5.3
In plain English
A medium-severity security flaw in grav-plugin-form from getgrav. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 30% of all known vulnerabilities).
Official description
The Grav Form plugin (getgrav/grav-plugin-form) versions 8.0.6 through 9.1.19 select the reCAPTCHA version to validate based solely on which response field key is present in the submitted payload. On a site configured for reCAPTCHA v3, an anonymous attacker can place their v3 token under the v2 field name (g-recaptcha-response instead of token), causing validation to use the v2 branch, which never applies the score threshold or verifies the expected action. This results in a complete bypass of reCAPTCHA v3 bot protection. The issue is fixed in version 9.1.20.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| getgrav | grav-plugin-form | 0 – before 9.1.20 |
Weakness: CWE-807 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
References
- GitHub Security Advisory (GHSA-89j6-8h38-2cc3) vendor-advisory
- VulnCheck Advisory: Grav Form Plugin before 9.1.20 reCAPTCHA v3 Authentication Bypass third-party-advisory