CVE-2026-21967
📋 TL;DR
An unauthenticated remote attacker can exploit this vulnerability in Oracle Hospitality OPERA 5 via HTTP to access, modify, or delete sensitive data, and cause partial service disruption. This affects specific versions of the OPERA 5 product used in hospitality management systems. Organizations using affected versions are at risk of data breaches and operational impacts.
💻 Affected Systems
- Oracle Hospitality OPERA 5
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of all OPERA 5 accessible data including guest information, financial records, and reservation systems, with unauthorized modifications and partial service disruption.
Likely Case
Unauthorized access to sensitive guest data (PII, payment information) and potential manipulation of reservation or billing records.
If Mitigated
Limited impact if network segmentation, strict access controls, and monitoring are implemented, though vulnerability remains exploitable.
🎯 Exploit Status
CVSS indicates low attack complexity and no authentication required, making exploitation straightforward for attackers with network access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Oracle's January 2026 Critical Patch Update for specific fixed versions
Vendor Advisory: https://www.oracle.com/security-alerts/cpujan2026.html
Restart Required: Yes
Instructions:
1. Review Oracle's January 2026 Critical Patch Update advisory. 2. Apply the relevant patches for OPERA 5. 3. Restart the OPERA 5 application/services. 4. Verify patch installation.
🔧 Temporary Workarounds
Network Segmentation
allRestrict network access to OPERA 5 servers to only trusted internal networks or specific IP ranges.
Web Application Firewall
allDeploy a WAF with rules to block suspicious HTTP requests targeting the Opera Servlet component.
🧯 If You Can't Patch
- Implement strict network access controls to limit HTTP traffic to OPERA 5 servers from authorized sources only.
- Enable detailed logging and monitoring for unusual HTTP requests or data access patterns to OPERA 5.
🔍 How to Verify
Check if Vulnerable:
Check the OPERA 5 version against affected versions listed in the CVE. Review Oracle's advisory for detailed vulnerability checking.Check Version:
Check within the OPERA 5 application interface or consult Oracle documentation for version query commands specific to your deployment.Verify Fix Applied:
Verify that the OPERA 5 version has been updated to a patched version as specified in Oracle's advisory. Test functionality after patching.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP requests to Opera Servlet endpoints from unauthenticated sources
- Unexpected data access or modification logs in OPERA 5 audit trails
Network Indicators:
- HTTP traffic to OPERA 5 servers from unexpected IP addresses or geolocations
- Anomalous patterns in data transfer volumes
SIEM Query:
Example: source="OPERA5" AND (http_method="POST" OR http_method="GET") AND user="unauthenticated" AND status="200"