CVE-2026-40565: FreeScout has Stored XSS / CSS Injection via linkify() — Unescaped URL in Anchor href

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-21 · updated 2026-06-17
Weakness: CWE-79

Description

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, FreeScout's linkify() function in app/Misc/Helper.php converts plain-text URLs in email bodies into HTML anchor tags without escaping double-quote characters (") in the URL. HTMLPurifier (called first via getCleanBody()) preserves literal " characters in text nodes. linkify() then wraps URLs including those " chars inside an unescaped href="..." attribute, breaking out of the href and injecting arbitrary HTML attributes. Version 1.8.213 fixes the issue.

Affected products

freescout-help-desk freescout: before 1.8.213 — fixed in 1.8.213

How to fix

Upgrade to a fixed version: freescout-help-desk freescout 1.8.213. Check the vendor advisory for mitigations.

References

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