CVE-2026-91479

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RDBMS Denial of Service in Oracle Database Server

Publication date: 2026-10-20

Last updated on: 2026-10-24

Assigner: Oracle

Description

Vulnerability in the RDBMS component of Oracle Database Server. Supported versions that are affected are 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 RDBMS executes to compromise RDBMS. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of RDBMS. CVSS 3.1 Base Score 6.5 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

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Meta Information

Published

2026-10-20

Last Modified

2026-10-24

Generated

2026-11-10

AI Q&A

2026-10-21

EPSS Evaluated

2026-11-08

NVD

CVE-2026-91479

EUVD

EUVD-2026-106724

Affected Vendors & Products

Vendor	Product	Version / Range
Oracle Corporation	Oracle Database Server	23.4.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-400	The product does not properly control the allocation and maintenance of a limited resource.

Attack-Flow Graph

Executive Summary

This is a vulnerability in the RDBMS component of Oracle Database Server affecting versions 23.4.0 to 23.26.3. An unauthenticated attacker with access to the physical network segment where the database runs can exploit it to cause a denial of service (DOS) by crashing or hanging the RDBMS repeatedly.

Detection Guidance

Detection of this vulnerability requires monitoring for unusual network traffic or database service behavior. Check for repeated crashes or hangs in the Oracle Database Server process. Inspect logs for unauthorized access attempts to the RDBMS component. Ensure network segmentation is enforced to limit physical access to the communication segment.

Impact Analysis

If exploited, this vulnerability could lead to frequent crashes or hangs of your Oracle Database Server, disrupting database availability and causing downtime for your applications and services.

Compliance Impact

This vulnerability causes denial-of-service (DOS) conditions in the Oracle Database Server RDBMS component. While it does not directly impact data confidentiality or integrity, prolonged unavailability of the database could lead to non-compliance with regulations like GDPR or HIPAA, which require timely access to personal or health data.

Mitigation Strategies

Apply the latest Oracle Database Server patch immediately to address the RDBMS vulnerability. Ensure network segmentation to restrict physical access to the communication segment where the RDBMS operates. Monitor for unusual database activity or crashes as potential indicators of exploitation.

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