---
id: "CVE-2026-112784"
kind: "vulnerability"
aliases: ["CVE-2026-112784"]
title: "OpenCATS: any logged-in user can send mail via SMTP relay"
severity: "medium"
cvss: 5.3
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["opencats", "package", "php", "self-hosted", "smtp"]
not_affected_if: ["version-0.10.0-or-later"]
published_at: "2026-10-20T11:17:18+00:00"
first_seen_at: "2026-10-23T21:57:20+00:00"
updated_at: "2026-10-25T04:24:51+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-112784", "first_seen_at": "2026-10-23T21:57:20+00:00"}]
---

# OpenCATS: any logged-in user can send mail via SMTP relay

OpenCATS before 0.10.0 lacks an authorization check on ajax/testEmailSettings.php, so any authenticated user, including read-only accounts, can trigger a test email. The attacker chooses the recipient and From address, enabling spoofed mail sent through the configured SMTP relay.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Look for `ajax/testEmailSettings.php` in the OpenCATS install directory
- Check the installed version against `0.10.0`; anything below is affected
- unknown whether the sources give a version-specific string check beyond this

## Fix

- Upgrade OpenCATS to `0.10.0` or later
- Until upgraded, restrict or disable access to `ajax/testEmailSettings.php` at the web server level
- Rotate the SMTP relay credentials if abuse is suspected

## Timeline

- 2026-10-23T21:57:20+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-112784

## From the sources

OpenCATS before 0.10.0 contains a missing authorization vulnerability in ajax/testEmailSettings.php that allows any authenticated user to send mail through the configured SMTP relay. Read-level users can supply testEmailAddress and fromAddress parameters to send the fixed test message to any recipient with a spoofed From address.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_