CVE-2026-22881
📋 TL;DR
A cross-site scripting vulnerability in the Message function of Cybozu Garoon allows attackers to inject malicious scripts that can reset arbitrary users' passwords. This affects Cybozu Garoon versions 5.15.0 through 6.0.3. Organizations using these versions are vulnerable to account compromise.
💻 Affected Systems
- Cybozu Garoon
⚠️ Risk & Real-World Impact
Worst Case
Attacker gains administrative access by resetting admin passwords, leading to complete system compromise and data exfiltration.
Likely Case
Attacker resets user passwords to gain unauthorized access to sensitive business information and internal systems.
If Mitigated
Limited impact due to proper input validation and output encoding preventing script execution.
🎯 Exploit Status
Exploitation requires the attacker to have access to send messages within the system to trigger the XSS payload.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 6.0.4
Vendor Advisory: https://kb.cybozu.support/article/39084/
Restart Required: Yes
Instructions:
1. Backup your Garoon database and configuration. 2. Download and install Garoon 6.0.4 from Cybozu support portal. 3. Apply the update following Cybozu's upgrade documentation. 4. Restart the Garoon service.
🔧 Temporary Workarounds
Disable Message Function
allTemporarily disable the vulnerable Message function to prevent exploitation.
Access Garoon administration panel > System Settings > Feature Settings > Disable 'Message' function
Implement WAF Rules
allConfigure web application firewall to block XSS payloads targeting the message function.
Add WAF rule: Detect and block scripts in message parameters containing 'password' or 'reset' keywords
🧯 If You Can't Patch
- Implement strict Content Security Policy (CSP) headers to prevent script execution from untrusted sources.
- Enable multi-factor authentication for all user accounts to mitigate password reset attacks.
🔍 How to Verify
Check if Vulnerable:
Check Garoon version in Administration > System Information. If version is between 5.15.0 and 6.0.3 inclusive, system is vulnerable.Check Version:
Check version via Garoon web interface: Administration > System InformationVerify Fix Applied:
Verify Garoon version is 6.0.4 or later in Administration > System Information.📡 Detection & Monitoring
Log Indicators:
- Unusual password reset activities
- Multiple failed login attempts after password reset
- Suspicious message content containing script tags
Network Indicators:
- HTTP requests to password reset endpoints with encoded script payloads
- Unusual traffic patterns to /garoon/message functions
SIEM Query:
source="garoon_logs" AND (event="password_reset" OR message_content MATCHES "<script>")