CVE-2026-40496

CRITICAL

FreeScout has Predictable Attachment Token that Allows Unauthenticated Private File Download via Brute Force

Title source: cna
STIX 2.1

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.

Scores

CVSS v3 9.1
EPSS 0.0040
EPSS Percentile 31.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact partial

Details

CWE
CWE-330 CWE-340
Status published
Products (2)
freescout/freescout < 1.8.213
freescout-help-desk/freescout < 1.8.213
Published Apr 21, 2026
Tracked Since Apr 21, 2026