freescout-help-desk freescout up to 1.8.219 Inject Message authentication spoofing

Summaryinfo

A vulnerability marked as critical has been reported in freescout-help-desk freescout up to 1.8.219. The impacted element is an unknown function of the component Inject Message Handler. The manipulation leads to authentication spoofing. This vulnerability is referenced as CVE-2026-47123. Remote exploitation of the attack is possible. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in freescout-help-desk freescout up to 1.8.219 and classified as critical. This issue affects an unknown code of the component Inject Message Handler. The manipulation with an unknown input leads to a authentication spoofing vulnerability. Using CWE to declare the problem leads to CWE-290. This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-47123 since 05/18/2026. The exploitation is known to be difficult. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Neither technical details nor an exploit are publicly available.

Upgrading to version 1.8.220 eliminates this vulnerability. Applying the patch d902f19038213c6a376947d269b00440908e88a0 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-33440). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• freescout-help-desk

Name

• freescout

Version

• 1.8.219

License

• open-source

Website

• Product: https://github.com/freescout-help-desk/freescout/

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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