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

Quick assessment

Affected
getgrav grav
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 表单插件（getgrav/grav-plugin-form）在 8.0.6 至 9.1.19 版本中，仅根据提交的数据负载中存在的响应字段键来选择验证所使用的 reCAPTCHA 版本。在配置为使用 reCAPTCHA v3 的站点上，匿名攻击者可以将他们的 v3 令牌放置在 v2 的字段名（ 而非 ）下，从而强制验证逻辑进入 v2 分支；而 v2 分支既不会应用分数阈值，也不会验证预期操作（action）。这导致 reCAPTCHA v3 的机器人防护被完全绕过。该问题已在 9.1.20 版本中修复。

CVSS 5.3 · Medium

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 2

VendorProduct Version RangeStatus
getgrav grav < 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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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

Affected Products

Vendor Product Affected Versions CPE Subscribe
getgrav grav 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 2.0.19 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
Same vendor: getgrav
Same weakness: CWE-807

V. Comments for CVE-2026-85602

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