CVE-2026-28474
📋 TL;DR
This vulnerability allows attackers to bypass allowlist restrictions in Nextcloud Talk by changing their display name to match an allowlisted user ID. Attackers can gain unauthorized access to restricted direct messages and rooms. Users of OpenClaw's Nextcloud Talk plugin versions before 2026.2.6 are affected.
💻 Affected Systems
- OpenClaw Nextcloud Talk plugin
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of private conversations, including sensitive business communications, intellectual property, or personal data in restricted channels.
Likely Case
Unauthorized access to private direct messages and team rooms, potentially leading to information disclosure and social engineering opportunities.
If Mitigated
Limited impact with proper monitoring and access controls, though the vulnerability still presents a significant authentication bypass risk.
🎯 Exploit Status
Exploitation requires a valid Nextcloud account but minimal technical skill - just changing display name to match allowlisted user ID.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2026.2.6
Vendor Advisory: https://github.com/openclaw/openclaw/security/advisories/GHSA-r5h9-vjqc-hq3r
Restart Required: No
Instructions:
1. Update OpenClaw Nextcloud Talk plugin to version 2026.2.6 or later via Nextcloud app store or manual installation. 2. Verify the update completed successfully. 3. No server restart required.
🔧 Temporary Workarounds
Disable allowlist features
allTemporarily disable DM and room allowlist functionality until patched
Restrict display name changes
allConfigure Nextcloud to prevent users from changing display names
🧯 If You Can't Patch
- Monitor user display name changes and alert on suspicious patterns
- Implement additional access controls and audit logs for sensitive conversations
🔍 How to Verify
Check if Vulnerable:
Check plugin version in Nextcloud admin settings under 'Apps' > 'Installed apps' > 'OpenClaw Talk'Check Version:
Check Nextcloud admin interface or run: grep -r 'version' /path/to/nextcloud/apps/openclaw_talk/appinfo/info.xmlVerify Fix Applied:
Confirm plugin version is 2026.2.6 or higher and test allowlist functionality📡 Detection & Monitoring
Log Indicators:
- User display name changes followed by access to restricted conversations
- Failed allowlist validation attempts
Network Indicators:
- Unauthorized access patterns to protected chat endpoints
SIEM Query:
source="nextcloud" AND (event="user_modified" OR event="chat_access") AND user_display_name_change=true