by Kastro
Paper/Archive/CVE-2026-85602

CVE-2026-85602

getgrav grav-plugin-form — Grav Form Plugin before 9.1.20 reCAPTCHA v3 Authentication Bypass

EPSS 0.4%public exploitCVSS 9.3
critical.is priorityof 100
44
CVSS 9.3 (CNA)9.3 / 10 × 3027.9Not in CISA KEV+300.0EPSS percentile 29.8.298 × 206.0Exploit: SSVC poc+1010.0SSVC exploitation: poc+100.0
Description · from the CVE record

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

ProductAffectedFixed inSource
grav-plugin-form< 9.1.209.1.20CNA

Scores by source

VulnCheck (CNA)9.3CVSS: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 (CNA)5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CISA ADPSSVCExploitation: poc · Automatable: yes · Technical impact: partial

References

exploitgithub.com/getgrav/grav/security/advisories/GHSA-89j6-8h38-2cc3writeupvulncheck.com/advisories/grav-form-plugin-before-9.1.20-recaptcha-v3-authentication-bypass