Vulnerability · Published Apr 21, 2026 · Assigned by GitHub_M

CVE-2026-40567FreeScout has HTML Injection in Outgoing Emails via Unsanitized Customer Name in Signature Variables

Medium 5.8

In plain English

A medium-severity security flaw in freescout from freescout-help-desk. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities).

Severity (CVSS 3.1)5.8Medium

Exploit odds (30 days)0.2%top 84.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

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.

Affected products (as reported)

Vendor	Product	Versions
freescout-help-desk	freescout	< 1.8.213

Weakness: CWE-116 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

References

https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-q8v4-v62h-5528 x_refsource_CONFIRM
https://github.com/freescout-help-desk/freescout/commit/9131b16f80eade81002cb9809a2603f6b61981cf x_refsource_MISC
https://github.com/freescout-help-desk/freescout/releases/tag/1.8.213 x_refsource_MISC