What’s Vulnerable › Vulnerabilities

CVE-2026-40591: FreeScout: Improper Authorization in Phone Conversation Creation Enables Cross-Mailbox Hidden Customer Modification

• Severity: high (CVSS 7.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-21 · updated 2026-06-17
• Weakness: CWE-639

Description

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.214, the phone-conversation creation flow accepts attacker-controlled `customer_id`, `name`, `to_email`, and `phone` values and resolves the target customer in the backend without enforcing mailbox-scoped customer visibility. As a result, a low-privileged agent who can create a phone conversation in Mailbox A can bind the new Mailbox A phone conversation to a hidden customer from Mailbox B and add a new alias email to that hidden customer record by supplying `to_email`. Version 1.8.214 fixes the vulnerability.

Affected products

• freescout-help-desk freescout: before 1.8.214

References

• https://github.com/freescout-help-desk/freescout/commit/83eea1ca47d97c6cdc90c501734bc2579b014a34
• https://github.com/freescout-help-desk/freescout/releases/tag/1.8.214
• https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-9ff4-mmhv-x6jp
• https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-9ff4-mmhv-x6jp

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