Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-63428— HeyForm: completeSubmission persists submitter-supplied hidden fields verbatim without validating against the form's declared hidden-field set

Quick assessment

Affected
heyform heyform
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.

HeyForm HeyForm是HeyForm公司的一款表单构建软件。 HeyForm 3.0.0-rc.9之前版本存在输入验证错误漏洞，该漏洞源于未验证 接收的 数组中 / 值，可能导致匿名表单提交者注入任意键值对，包括XSS有效载荷、假授权元数据和集成相关值。

CVSS 5.8 · Medium EPSS 0.34% · P27

Affected Version Matrix 1

VendorProduct Version RangeStatus
heyform heyform < 3.0.0-rc.9 affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-63428

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.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
HeyForm: completeSubmission persists submitter-supplied hidden fields verbatim without validating against the form's declared hidden-field set
Source: CVE Program / CVE List V5
Vulnerability Description
HeyForm is an open-source form builder. Prior to version 3.0.0-rc.9, `completeSubmission` accepts a `hiddenFields: [{id, name, value}]` array from the submitter and stores it verbatim in `submission.hiddenFields`, without validating the supplied `id`/`name` against the form's declared `form.hiddenFields` schema. An anonymous form submitter can therefore inject arbitrary key/value pairs (including XSS payloads, fake authorization metadata, integration-relevant values) into the stored submission. These fields are subsequently forwarded as-is to every webhook integration registered on the form. Version 3.0.0-rc.9 contains a patch for the issue.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
输入验证不恰当
Source: CVE Program / CVE List V5
Vulnerability Title
HeyForm 输入验证错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
HeyForm HeyForm是HeyForm公司的一款表单构建软件。 HeyForm 3.0.0-rc.9之前版本存在输入验证错误漏洞，该漏洞源于未验证`completeSubmission`接收的`hiddenFields`数组中`id`/`name`值，可能导致匿名表单提交者注入任意键值对，包括XSS有效载荷、假授权元数据和集成相关值。
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
heyform heyform < 3.0.0-rc.9 -

II. Public POCs for CVE-2026-63428

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-63428

请登录查看更多情报信息。

Vendor Advisories for CVE-2026-63428 (1)

Same Patch Batch · heyform · 2026-07-20 · 4 CVEs total

CVE-2026-35198 9.0 CRITICAL HeyForm vulnerable to stored XSS via form field titles
CVE-2026-63429 8.6 HIGH HeyForm has unauthenticated /api/upload endpoint that accepts arbitrary files with no auth
CVE-2026-45797 HeyForm Vulnerable to Stored XSS via Unauthenticated SVG File Upload

IV. Related Vulnerabilities

Same product: heyform
Same vendor: heyform
Same weakness: CWE-20