What’s Vulnerable › Vulnerabilities

CVE-2026-47123: FreeScout: Agent Impersonation via Missing HMAC Verification on Notification Reply Message-ID Path

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-29 · updated 2026-07-22
• Weakness: CWE-290

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.

Affected products

• freescout-help-desk freescout: before 1.8.220

References

• https://github.com/freescout-help-desk/freescout/commit/d902f19038213c6a376947d269b00440908e88a0
• https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-6r38-6mcf-2ww3
• https://vincent.vulcoord.net/score/?state=Not+Scored&year=2026&year=2025&assigned_to=a165dae3-480e-4f7d-bbb8-9b1d78115b69&cve=CVE-2026-47123&analyze=1

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