CVE-2026-22888
📋 TL;DR
An improper input verification vulnerability in Cybozu Garoon allows attackers to modify portal settings without proper authorization. This could block legitimate users from accessing the system. Affects Garoon versions 5.0.0 through 6.0.3.
💻 Affected Systems
- Cybozu Garoon
⚠️ Risk & Real-World Impact
Worst Case
Attackers could modify portal settings to block all user access, causing complete service disruption and requiring administrative intervention to restore functionality.
Likely Case
Unauthorized modification of portal settings leading to partial service disruption for affected users or groups.
If Mitigated
Minimal impact with proper access controls and monitoring in place to detect unauthorized configuration changes.
🎯 Exploit Status
Requires authenticated access to exploit, but specific authentication level not detailed in available references.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 6.0.4 or later
Vendor Advisory: https://kb.cybozu.support/article/39083/
Restart Required: Yes
Instructions:
1. Backup your Garoon installation and database. 2. Download Garoon 6.0.4 or later from Cybozu support portal. 3. Follow Cybozu's upgrade documentation to apply the update. 4. Restart the Garoon service. 5. Verify the update was successful.
🔧 Temporary Workarounds
Restrict Access Controls
allTighten access controls to limit who can modify portal settings to only essential administrators.
🧯 If You Can't Patch
- Implement strict network segmentation to limit access to Garoon administration interfaces
- Enable detailed logging of all portal configuration changes and monitor for unauthorized modifications
🔍 How to Verify
Check if Vulnerable:
Check Garoon version in administration console or via system information page. If version is between 5.0.0 and 6.0.3 inclusive, system is vulnerable.Check Version:
Check via Garoon web interface: Administration > System Information > VersionVerify Fix Applied:
Verify Garoon version is 6.0.4 or later in administration console. Test portal settings modification with non-admin accounts to confirm proper authorization checks.📡 Detection & Monitoring
Log Indicators:
- Unauthorized portal setting modification attempts
- Configuration changes from unexpected user accounts or IP addresses
Network Indicators:
- Unusual patterns of requests to portal configuration endpoints
SIEM Query:
source="garoon" AND (event_type="configuration_change" OR action="modify_portal") AND user NOT IN [admin_users]