CVE-2026-40497: FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, FreeScout's `Helper::stripDangerousTags()` removes ``, ``, ``, `` but…

PriorityP340high8.1CVSS 3.1

AVNACLPRHUIRSCCHIHAN

EPSS

0.24%

15.4th percentile

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, FreeScout's `Helper::stripDangerousTags()` removes ``, ``, ``, `` but does NOT strip `` 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 `` tags, leaving CSS injection possible. Version 1.8.213 contains an updated fix.

Affected

2 ranges

Vendor	Product	Version range	Fixed in
freescout-help-desk	freescout	< 1.8.213	1.8.213
freescout	freescout	< 1.8.213	1.8.213

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