CVE-2026-34311: Oracle Hospitality OPERA 5 Property Services Unauthenticated Remote Takeover

CVE-2026-34311 is a critical vulnerability affecting Oracle Hospitality OPERA 5 Property Services. The vulnerability resides within the Opera component and impacts versions 5.6.19.24, 5.6.22, 5.6.25.19, 5.6.27.6, and 5.6.28. An unauthenticated attacker with network access can exploit this vulnerability via HTTP, potentially leading to a complete takeover of the Oracle Hospitality OPERA 5 Property Services application. This vulnerability poses a significant risk to organizations using the affected versions, as it allows for unauthorized access, data manipulation, and service disruption. Due to the ease of exploitation and the high impact, immediate patching or mitigation is crucial.

Attack Chain

1. The attacker identifies a vulnerable Oracle Hospitality OPERA 5 Property Services instance accessible over the network via HTTP.
2. The attacker sends a crafted HTTP request to the vulnerable Opera component, exploiting CVE-2026-34311.
3. The vulnerability allows the attacker to bypass authentication mechanisms due to a flaw in how requests are processed.
4. Successful exploitation grants the attacker unauthorized access to the Oracle Hospitality OPERA 5 Property Services application.
5. The attacker leverages this access to execute arbitrary code within the context of the application.
6. The attacker escalates privileges to gain complete control over the OPERA 5 Property Services instance.
7. The attacker installs malware or modifies system configurations to maintain persistent access.
8. The attacker exfiltrates sensitive data, disrupts services, or performs other malicious activities, achieving complete takeover of the OPERA 5 Property Services.

Impact

Successful exploitation of CVE-2026-34311 can lead to a complete takeover of the Oracle Hospitality OPERA 5 Property Services application. This could result in significant data breaches, financial losses, reputational damage, and disruption of services. Due to the high CVSS score (9.8), the vulnerability is easily exploitable and presents a severe risk to organizations using the affected versions. The lack of required authentication makes it particularly dangerous, as any attacker with network access can potentially compromise the system.

Recommendation

• Apply the security patch provided by Oracle to address CVE-2026-34311 on all affected Oracle Hospitality OPERA 5 Property Services instances immediately.
• Implement network segmentation to limit network access to the Oracle Hospitality OPERA 5 Property Services application, reducing the attack surface.
• Deploy the Sigma rule Detect CVE-2026-34311 Exploitation Attempt — Suspicious HTTP Request to identify potential exploitation attempts based on specific HTTP patterns.
• Monitor web server logs for suspicious HTTP requests targeting the Opera component of Oracle Hospitality OPERA 5 Property Services.