CVE-2025-54366

FreeScout's deserialization of untrusted data leads to Remote Code Execution

HIGH
8.8
CVSS Score
Published: July 26, 2025 at 03:35 AM UTC
Updated: June 17, 2026 at 09:39 AM UTC
2 products affected across 2 vendorsFreescoutFreescout

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Severity
HIGH8.8
Exploit prediction
EPSS 1%
SSVC
PoC

Description

FreeScout is a lightweight free open source help desk and shared inbox built with PHP (Laravel framework). In versions 1.8.185 and below, there is a critical deserialization vulnerability in the /conversation/ajax endpoint that allows authenticated users with knowledge of the APP_KEY to achieve remote code execution. The vulnerability occurs when the application processes the attachments_all and attachments POST parameters through the insecure Helper::decrypt() function, which performs unsafe deserialization of user-controlled data without proper validation. This flaw enables attackers to create arbitrary objects and manipulate their properties, leading to complete compromise of the web application. This is fixed in version 1.8.186.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.8.86
Affected range stops below 1.8.86, so it looks safe — our inference, not a vendor statement
v < 1.8.186
Affected range stops below 1.8.186, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-502

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