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CVE-2026-85602— Grav Form Plugin before 9.1.20 reCAPTCHA v3 Authentication Bypass

Quick assessment

Affected
getgrav grav-plugin-form
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

grav-plugin-form是Grav组织开源的一款用于构建和管理网页表单的扩展组件。 grav-plugin-form 8.0.6版本至9.1.19版本存在输入验证错误漏洞，该漏洞源于插件仅根据提交负载中的响应字段键选择reCAPTCHA验证版本，在配置reCAPTCHA v3的站点上，匿名攻击者可通过将v3令牌放入v2字段名（g-recaptcha-response）使验证进入v2分支，从而完全绕过reCAPTCHA v3机器人保护。

CVSS 5.3 · Medium EPSS 0.36% · P29

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 2

VendorProduct Version RangeStatus
getgrav grav-plugin-form < 9.1.20 affected
9.1.20 unaffected
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I. Basic Information for CVE-2026-85602

Vulnerability Information
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Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
Grav Form Plugin before 9.1.20 reCAPTCHA v3 Authentication Bypass
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
在安全决策中依赖未经信任的输入
Source: CVE Program / CVE List V5
Vulnerability Title
grav-plugin-form 输入验证错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
grav-plugin-form是Grav组织开源的一款用于构建和管理网页表单的扩展组件。 grav-plugin-form 8.0.6版本至9.1.19版本存在输入验证错误漏洞，该漏洞源于插件仅根据提交负载中的响应字段键选择reCAPTCHA验证版本，在配置reCAPTCHA v3的站点上，匿名攻击者可通过将v3令牌放入v2字段名（g-recaptcha-response）使验证进入v2分支，从而完全绕过reCAPTCHA v3机器人保护。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
getgrav grav-plugin-form 0 ~ 9.1.20 -

II. Public POCs for CVE-2026-85602

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III. Intelligence Information for CVE-2026-85602

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Vendor Advisories for CVE-2026-85602 (2)

Same Patch Batch · getgrav · 2026-09-04 · 7 CVEs total

CVE-2026-85604 8.8 HIGH Grav before 2.0.18 Remote Code Execution via sort filter
CVE-2026-85599 7.2 HIGH Grav Shortcode Core before 6.2.5 Stored XSS via unescaped parameters
CVE-2026-85603 6.5 MEDIUM Grav Admin Plugin Path Traversal via Save As Language Code
CVE-2026-85598 6.4 MEDIUM Grav 2.0.0 through 2.0.17 Stored XSS via Modular Pages
CVE-2026-85600 5.4 MEDIUM Grav Admin before 2.0.21 Stored XSS via username
CVE-2026-85601 5.4 MEDIUM Grav Admin before 2.0.20 Cross-Site Scripting via marked.js

IV. Related Vulnerabilities

Same product: grav-plugin-form
Same vendor: getgrav
Same weakness: CWE-807

V. Comments for CVE-2026-85602

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