CVE-2026-83350

Received Received - Intake

Oracle Net Services Denial of Service Vulnerability

Publication date: 2026-09-15

Last updated on: 2026-09-16

Assigner: Oracle

Description

Vulnerability in the Oracle Net Services component of Oracle Database Server. Supported versions that are affected are 21.3-21.23 and 23.4.0-23.26.3. Easily exploitable vulnerability allows unauthenticated attacker with network access via Oracle Net to compromise Oracle Net Services. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of Oracle Net Services. CVSS 3.1 Base Score 7.5 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-09-15

Last Modified

2026-09-16

Generated

2026-10-06

AI Q&A

2026-09-16

EPSS Evaluated

2026-10-04

NVD

CVE-2026-83350

EUVD

EUVD-2026-79703

Affected Vendors & Products

Vendor	Product	Version / Range
oracle	database_server	From 21.3 (inc) to 21.23 (inc)
oracle	database_server	From 23.4.0 (inc) to 23.26.3 (inc)

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 Oracle Net Services, a component of Oracle Database Server. It affects versions 21.3-21.23 and 23.4.0-23.26.3. An unauthenticated attacker can exploit it remotely via Oracle Net to cause a denial of service (DOS) by crashing or hanging the service repeatedly.

Detection Guidance

Detection requires checking Oracle Database Server versions 21.3-21.23 or 23.4.0-23.26.3. Verify installed versions using Oracle utilities like SQL*Plus with 'SELECT * FROM v$version;' or OS commands like 'lsnrctl status' for listener details. Monitor for crashes or hangs in Oracle Net Services.

Impact Analysis

If exploited, this vulnerability can disrupt database operations by making Oracle Net Services unavailable. This could lead to downtime, loss of access to critical database functions, and potential disruption of services relying on the database.

Compliance Impact

This vulnerability causes denial-of-service (DOS) conditions in Oracle Net Services, leading to system unavailability. Such disruptions can impact data access and processing, potentially violating availability requirements in GDPR (Article 32) and HIPAA (Security Rule §164.312(a)(2)(ii)).

Mitigation Strategies

Apply the latest Oracle Critical Patch Update (CPU) for Oracle Database Server to address the vulnerability in Oracle Net Services. Monitor Oracle's security advisories for patches and updates. Ensure network access controls are in place to restrict unauthorized access to Oracle Net Services ports.

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