CVE-2026-107393 FreeScout: Stored HTML Injection in Administrator Alert Emails via Spoofed CF-Connecting-IP Header
Attackers can inject malicious HTML into admin alert emails via spoofed headers, potentially executing code or stealing sessions when admins view the email.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-107393?
CVE-2026-107393 is a medium-severity cross-site scripting vulnerability in freescout-help-desk freescout, published on 8 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
FreeScout is a self-hosted help desk and shared mailbox. Prior to 1.8.235, when APP_CLOUDFLARE_IS_USED is enabled, FreeScout trusts an unvalidated CF-Connecting-IP header during failed login attempts and stores the spoofed value in the activity log. LogsMonitor inserts the value into an administrator alert email without HTML escaping, allowing injected HTML to execute when an administrator opens the email. This issue is fixed in version 1.8.235.
Which versions are affected by CVE-2026-107393?
How do I fix CVE-2026-107393?
No fix has been published for CVE-2026-107393 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-2026-107393 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-107393 exists.
Sources
Also known as GHSA-9cm3-qvj2-8hg4.