CVE-2026-16867

Undergoing Analysis Undergoing Analysis - In Progress

Authentication Bypass in IBM i via NTLM Session Negotiation

Publication date: 2026-08-13

Last updated on: 2026-08-13

Assigner: IBM Corporation

Description

IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote attacker to access server resources with the privileges of an authenticated user due to improper authentication during NTLM session negotiation.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-08-13

Last Modified

2026-08-13

Generated

2026-08-14

AI Q&A

2026-08-14

EPSS Evaluated

N/A

NVD

CVE-2026-16867

EUVD

EUVD-2026-58373

Affected Vendors & Products

Vendor	Product	Version / Range
ibm	i	7.6
ibm	i	7.5
ibm	i	7.4
ibm	i	7.3

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-287	When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

Attack-Flow Graph

Executive Summary

This vulnerability in IBM i 7.6, 7.5, 7.4, and 7.3 allows a remote attacker to access server resources with the privileges of an authenticated user. The issue occurs due to improper authentication during NTLM session negotiation, potentially enabling unauthorized access.

Impact Analysis

An attacker could exploit this to gain elevated access to server resources, leading to data breaches, unauthorized modifications, or disruption of services. The high CVSS score (8.1) indicates significant risk of confidentiality, integrity, and availability impacts.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, violating GDPR (data protection) and HIPAA (health information privacy) requirements. Non-compliance may result in legal penalties, fines, or reputational damage.

Mitigation Strategies

Disable NTLM authentication if possible and enforce stronger authentication methods like Kerberos. Apply IBM i PTFs or updates addressing improper NTLM session negotiation. Monitor network traffic for unusual authentication attempts.

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