CVE-2026-71063 in Database Server
Summary
by MITRE • 08/19/2026
Vulnerability in the Portable Clusterware component of Oracle Database Server. Supported versions that are affected are 19.3-19.32, 21.3-21.23 and 23.4.0-23.26.3. Easily exploitable vulnerability allows unauthenticated attacker with access to the physical communication segment attached to the hardware where the Portable Clusterware executes to compromise Portable Clusterware. While the vulnerability is in Portable Clusterware, attacks may significantly impact additional products (scope change). Successful attacks of this vulnerability can result in takeover of Portable Clusterware. CVSS 3.1 Base Score 9.6 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H).
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Analysis
by VulDB Data Team • 08/19/2026
The identified vulnerability resides within the Portable Clusterware component of Oracle Database Server, affecting supported versions including 19.3 through 19.32, 21.3 through 21.23, and 23.4.0 through 23.26.3. This security flaw is classified as a critical severity issue with a CVSS 3.1 Base Score of 9.6, indicating severe impacts on confidentiality, integrity, and availability. The vulnerability allows for an unauthenticated attacker to compromise the Portable Clusterware service provided they have access to the physical communication segment attached to the hardware where the component executes. This specific attack vector highlights that while the immediate target is the cluster management software, the operational scope of a successful exploit extends significantly beyond this single component due to its central role in database high availability and failover mechanisms.
From a technical perspective, the flaw enables an attacker who possesses local network access on the same physical segment as the Oracle Clusterware nodes to gain unauthorized control over the Portable Clusterware process. This level of compromise is particularly dangerous because clusterware manages node membership, resource allocation, and failover decisions across a database cluster. By taking over this component, an adversary can manipulate how resources are distributed among nodes or disrupt communication between them. The lack of required authentication for exploitation means that any device connected to the same network segment as the vulnerable Oracle servers is potentially within reach of an attacker who has gained initial foothold on that local area network or physical infrastructure layer.
The operational impact of this vulnerability is profound, extending well beyond the immediate compromise of the clusterware software itself. Because Portable Clusterware orchestrates the availability and consistency of the entire database environment, its takeover can lead to a complete denial of service for critical business applications relying on these databases. Furthermore, an attacker with control over cluster operations could potentially manipulate data replication processes or trigger unintended failovers that result in data corruption or loss. The scope change mentioned in the advisory underscores that while the code defect is isolated to one component, the resulting state allows for broader system compromise, affecting all database instances and associated services managed by that cluster infrastructure.
In terms of industry standard classifications, this vulnerability aligns with CWE-287 Improper Authentication, as it permits unauthenticated access to a critical administrative function. Additionally, given the ability to take over control of the system components, it relates closely to CWE-269 Improvement of Privileges and potentially CWE-434 Unrestricted Upload of File with Dangerous Type if file manipulation is involved in the takeover process. From an offensive security perspective, this aligns with MITRE ATT&CK techniques involving Lateral Movement via Remote Services or System Network Discovery, as attackers would likely use this foothold to map out further targets within the database environment and escalate their privileges to gain persistent access to sensitive data stores.
Mitigation strategies must prioritize immediate patching of all affected Oracle Database Server versions to 19.32+, 21.23+, or 23.26.4+ depending on the specific track in use, as these releases contain the necessary code fixes for this clusterware flaw. In environments where patching is not immediately feasible, network segmentation should be strictly enforced to ensure that only authorized management interfaces and trusted application servers can communicate with the Oracle Clusterware ports over Layer 2 or Layer 3 boundaries. Implementing strict access control lists on switches connecting database nodes can limit exposure to untrusted physical segments. Additionally, monitoring for unusual cluster state changes, unexpected node evictions, or unauthorized resource movements can help detect exploitation attempts in real-time before significant damage occurs to the underlying data integrity and availability.