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

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-40497— FreeScout Vulnerable to CSS Injection via Stored Style Tag in Mailbox Signature (CSRF Token Exfiltration)

Quick assessment

Affected
freescout-help-desk freescout
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.

FreeScout是FreeScout公司的一个使用 PHP（Laravel 框架）构建的超轻量级且功能强大的免费开源帮助台和共享收件箱。 FreeScout 1.8.213之前版本存在安全漏洞，该漏洞源于Helper::stripDangerousTags函数未移除style标签，可能导致具有邮箱设置访问权限的攻击者注入CSS属性选择器窃取CSRF令牌，进而执行权限提升。

CVSS 8.1 · High EPSS 0.43% · P35
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-40497

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Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.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
FreeScout Vulnerable to CSS Injection via Stored Style Tag in Mailbox Signature (CSRF Token Exfiltration)
Source: CVE Program / CVE List V5
Vulnerability Description
FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, FreeScout's `Helper::stripDangerousTags()` removes `<script>`, `<form>`, `<iframe>`, `<object>` but does NOT strip `<style>` tags. The mailbox signature field is saved via POST /mailbox/settings/{id} and later rendered unescaped via `{!! $conversation->getSignatureProcessed([], true) !!}` in conversation views. CSP allows `style-src * 'self' 'unsafe-inline'`, so injected inline styles execute freely. An attacker with access to mailbox settings (admin or agent with mailbox permission) can inject CSS attribute selectors to exfiltrate the CSRF token of any agent/admin who views a conversation in that mailbox. With the CSRF token, the attacker can perform any state-changing action as the victim (create admin accounts, change email/password, etc.) — privilege escalation from agent to admin. This is the result of an incomplete fix of GHSA-jqjf-f566-485j. That advisory reported XSS via mailbox signature. The fix applied `Helper::stripDangerousTags()` to the signature before saving. However, `stripDangerousTags()` only removes `script`, `form`, `iframe`, and `object` tags — it does NOT strip `<style>` tags, leaving CSS injection possible. Version 1.8.213 contains an updated fix.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
在Web页面生成时对输入的转义处理不恰当(跨站脚本)
Source: CVE Program / CVE List V5
Vulnerability Title
FreeScout 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
FreeScout是FreeScout公司的一个使用 PHP（Laravel 框架）构建的超轻量级且功能强大的免费开源帮助台和共享收件箱。 FreeScout 1.8.213之前版本存在安全漏洞，该漏洞源于Helper::stripDangerousTags函数未移除style标签，可能导致具有邮箱设置访问权限的攻击者注入CSS属性选择器窃取CSRF令牌，进而执行权限提升。
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
freescout-help-desk freescout < 1.8.213 -

II. Public POCs for CVE-2026-40497

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

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-40497

请登录查看更多情报信息。

Vendor Advisories for CVE-2026-40497 (1)

Vendor Pages for CVE-2026-40497 (1)

Same Patch Batch · freescout-help-desk · 2026-04-21 · 20 CVEs total

CVE-2026-41193 9.1 CRITICAL FreeScout has Zip Slip path traversal in module installation that allows arbitrary file wr
CVE-2026-40569 9.0 CRITICAL FreeScout's Mass Assignment in Mailbox Connection Settings Enables Silent Email Exfiltrati
CVE-2026-40568 8.5 HIGH FreeScout Vulnerable to XSS via Mailbox Signature Due to Incomplete HTML Sanitization
CVE-2026-40589 7.6 HIGH FreeScout has Customer Edit Cross-Mailbox Email Takeover
CVE-2026-41190 7.1 HIGH FreeScout has assigned-only visibility bypass via save_draft that allows hidden conversati
CVE-2026-41189 7.1 HIGH FreeScout has assigned-only visibility bypass that allows editing hidden customer-authored
CVE-2026-41191 7.1 HIGH FreeScout's signature only mailbox permission allows unauthorized mailbox chat setting cha
CVE-2026-41192 7.1 HIGH FreeScout's client-controlled attachment IDs allow deletion of existing conversation attac
CVE-2026-40591 7.1 HIGH FreeScout: Improper Authorization in Phone Conversation Creation Enables Cross-Mailbox Hid
CVE-2026-40565 6.1 MEDIUM FreeScout has Stored XSS / CSS Injection via linkify() — Unescaped URL in Anchor href
CVE-2026-40592 5.9 MEDIUM FreeScout's cross-user undo reply allows mailbox peers to recall another agent's outbound
CVE-2026-40567 5.8 MEDIUM FreeScout has HTML Injection in Outgoing Emails via Unsanitized Customer Name in Signature
CVE-2026-41194 5.4 MEDIUM FreeScout's Mailbox OAuth disconnect uses a state-changing GET and is CSRFable
CVE-2026-41183 4.3 MEDIUM FreeScout allows non-folder conversation queries to disclose assigned-only hidden conversa
CVE-2026-40590 4.3 MEDIUM FreeScout's Customer AJAX Create Modifies Hidden Existing Customer
CVE-2026-40566 4.1 MEDIUM FreeScout vulnerable to SSRF via IMAP/SMTP Connection Test Endpoints
CVE-2026-40570 FreeScout's Missing Authorization in load_customer_info Allows Any Authenticated User to A
CVE-2026-40496 FreeScout has Predictable Attachment Token that Allows Unauthenticated Private File Downlo
CVE-2026-40498 FreeScout has Authentication Bypass and Information Disclosure in SystemController via /sy

IV. Related Vulnerabilities

Same product: freescout
Same vendor: freescout-help-desk
Same weakness: CWE-79

V. Comments for CVE-2026-40497

No comments yet

Leave a comment