CVE-2026-85602
Grav Form Plugin before 9.1.20 reCAPTCHA v3 Authentication Bypass
- State
- Published
- Severity
- 9.3 Critical
- Published
- Sep 4, 2026
- Updated
- Sep 5, 2026
- Reserved
- Sep 4, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 9.3 Critical | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 5.3 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N | VulnCheck |
Weaknesses
- CWE-807 Reliance on Untrusted Inputs in a Security Decision
Affected Products
| Product | Versions |
|---|---|
grav-plugin-formgetgrav |
|
References
- GitHub Security Advisory (GHSA-89j6-8h38-2cc3)vendor-advisory
- VulnCheck Advisory: Grav Form Plugin before 9.1.20 reCAPTCHA v3 Authentication Bypassthird-party-advisory
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