CVE-2026-40567 FreeScout has HTML Injection in Outgoing Emails via Unsanitized Customer Name in Signature Variables
Unauthenticated attackers can inject HTML into outgoing support emails via crafted sender names, enabling phishing and tracking pixel attacks.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-40567?
CVE-2026-40567 is a medium-severity cross-site scripting vulnerability in freescout-help-desk freescout, published on 21 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, an unauthenticated attacker can inject arbitrary HTML into outgoing emails generated by FreeScout by sending an email with a crafted From display name. The name is stored in the database without sanitization and rendered unescaped into outgoing reply emails via the `{%customer.fullName%}` signature variable. This allows embedding phishing links, tracking pixels, and spoofed content inside legitimate support emails sent from the organization's address. Version 1.8.213 fixes the issue.
Weakness: CWE-116
Which versions are affected by CVE-2026-40567?
How do I fix CVE-2026-40567?
No fix has been published for CVE-2026-40567 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-40567 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40567 exists.
Sources
Also known as GHSA-q8v4-v62h-5528.