CVE-2026-21966
📋 TL;DR
An unauthenticated attacker can exploit this vulnerability in Oracle Hospitality OPERA 5 Property Services via HTTP to modify or read limited data, requiring user interaction. Affected versions are 5.6.19.23, 5.6.25.17, 5.6.26.10, and 5.6.27.4. The attack can impact other products beyond OPERA 5 Property Services.
💻 Affected Systems
- Oracle Hospitality OPERA 5 Property Services
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Unauthorized data modification and exfiltration across connected systems, potentially affecting hotel operations and guest data.
Likely Case
Limited data tampering or unauthorized viewing of OPERA 5 Property Services data by an external attacker.
If Mitigated
Minimal impact if network segmentation and access controls prevent unauthenticated HTTP access.
🎯 Exploit Status
Easily exploitable via HTTP, but requires user interaction (UI:R).
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Oracle advisory for patched versions
Vendor Advisory: https://www.oracle.com/security-alerts/cpujan2026.html
Restart Required: Yes
Instructions:
1. Review Oracle advisory for patched versions. 2. Apply the relevant patch from Oracle. 3. Restart the OPERA 5 Property Services application.
🔧 Temporary Workarounds
Network Segmentation
allRestrict HTTP access to OPERA 5 Property Services to trusted networks only.
Web Application Firewall
allDeploy a WAF to block malicious HTTP requests targeting OPERA 5.
🧯 If You Can't Patch
- Implement strict network access controls to limit HTTP traffic to OPERA 5 Property Services.
- Monitor for unusual HTTP requests or data access patterns.
🔍 How to Verify
Check if Vulnerable:
Check the OPERA 5 Property Services version against affected versions: 5.6.19.23, 5.6.25.17, 5.6.26.10, 5.6.27.4.Check Version:
Check within the OPERA 5 application interface or configuration files for version details.Verify Fix Applied:
Verify the version is updated to a patched release as specified in the Oracle advisory.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP requests to OPERA 5 endpoints from unauthenticated sources.
- Unexpected data modifications or access logs in OPERA 5.
Network Indicators:
- HTTP traffic to OPERA 5 Property Services from untrusted IPs.
SIEM Query:
source="OPERA5" AND (http_method="POST" OR http_method="GET") AND user="unauthenticated"