FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to 1.8.220, the email processing pipeline in FreeScout's FetchEmails command has two code paths for identifying agent (user) replies based on In-Reply-To / References headers. The notification reply path (notify-{thread_id}-{user_id}-...) extracts thread_id and user_id directly from the Message-ID without HMAC verification. An external attacker who can spoof the From address of a helpdesk agent can inject messages that FreeScout processes as legitimate agent replies — which are then automatically forwarded to customers via the legitimate SMTP server. This vulnerability is fixed in 1.8.220.

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Fixes

Solution

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History

Fri, 29 May 2026 22:15:00 +0000

Type Values Removed Values Added
First Time appeared Freescout Helpdesk
Freescout Helpdesk freescout
Vendors & Products Freescout Helpdesk
Freescout Helpdesk freescout

Fri, 29 May 2026 20:15:00 +0000

Type Values Removed Values Added
Description FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to 1.8.220, the email processing pipeline in FreeScout's FetchEmails command has two code paths for identifying agent (user) replies based on In-Reply-To / References headers. The notification reply path (notify-{thread_id}-{user_id}-...) extracts thread_id and user_id directly from the Message-ID without HMAC verification. An external attacker who can spoof the From address of a helpdesk agent can inject messages that FreeScout processes as legitimate agent replies — which are then automatically forwarded to customers via the legitimate SMTP server. This vulnerability is fixed in 1.8.220.
Title FreeScout: Agent Impersonation via Missing HMAC Verification on Notification Reply Message-ID Path
Weaknesses CWE-290
CWE-345
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-29T19:51:41.383Z

Reserved: 2026-05-18T19:50:18.694Z

Link: CVE-2026-47123

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-05-29T20:16:28.380

Modified: 2026-05-29T20:21:38.773

Link: CVE-2026-47123

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-29T22:30:09Z

Weaknesses