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

FreeScout Vulnerable to CSS Injection via Stored Style Tag in Mailbox Signature (CSRF Token Exfiltration)

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.

CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N

在Web页面生成时对输入的转义处理不恰当(跨站脚本)

FreeScout 安全漏洞

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。

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