What’s Vulnerable › Vulnerabilities

CVE-2026-40496: FreeScout has Predictable Attachment Token that Allows Unauthenticated Private File Download via Brute Force

• Severity: critical (CVSS 9.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-04-21 · updated 2026-06-17
• Weakness: CWE-330

Description

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, attachment download tokens are generated using a weak and predictable formula: `md5(APP_KEY + attachment_id + size)`. Since attachment_id is sequential and size can be brute-forced in a small range, an unauthenticated attacker can forge valid tokens and download any private attachment without credentials. 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

• https://github.com/freescout-help-desk/freescout/commit/dbdf8f2260b43a21818255c70f0b61b9de9cd555
• https://github.com/freescout-help-desk/freescout/releases/tag/1.8.213
• https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-2783-wxmm-wmwr

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