Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2026-40496

Severity CVSS v4.0:
HIGH
Type:
CWE-330 Use of Insufficiently Random Value
Publication date:
21/04/2026
Last modified:
21/04/2026

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.

Impact

Vector 4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P CVSS v4.0 Severity and Metrics:

Base Score: 8.80 HIGH
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): None
Privileges Required (PR): None
User Interaction (UI): None
Confidentiality (VC): High
Integrity (VI): High
Availability (VA): None
Confidentiality (SC): None
Integrity (SI): None
Availability (SA): None
Exploit Maturity (E): POC

Base Score 4.0
8.80
Severity 4.0
HIGH

References to Advisories, Solutions, and Tools