Description

IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote authenticated attacker to inject arbitrary content into Navigator log files due to improper output neutralization for logs.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "4.3",
  "pubDate": "2026-08-12T20:17:41.063Z",
  "pubdate": "2026-08-12T20:17:41.063Z",
  "executiveSummary": "A log injection vulnerability exists in IBM i versions 7.6, 7.5, 7.4, and 7.3, specifically within the Navigator logging mechanism. This flaw stems from improper output neutralization of data written to log files. An attacker capable of remote authentication can leverage this weakness to inject arbitrary content, including malicious strings or falsified log entries, directly into Navigator log files. The primary impact involves log integrity compromise, which can hinder forensic investigations, obscure malicious post-exploitation activities, or facilitate downstream log-parsing attacks if the logs are consumed by insecure Security Information and Event Management (SIEM) systems or administrative tools. The attack requires remote authentication and leverages valid user privileges to interact with the vulnerable logging component. While the vulnerability does not inherently grant remote code execution or direct system access, the ability to manipulate audit trails poses severe compliance, monitoring, and incident response implications for enterprise environments relying on IBM i infrastructure.",
  "technicalDetails": "The vulnerability resides in the logging subsystem of IBM i Navigator across versions 7.6, 7.5, 7.4, and 7.3. The root cause is the lack of proper input sanitization and output neutralization before writing user-supplied or application-derived data to Navigator log files. Specifically, control characters, newlines, or structured log syntax delimiters provided by an authenticated user are not adequately filtered, encoded, or escaped by the logging function.\nExploitation requires the attacker to possess valid remote authentication credentials to access the IBM i Navigator interface or underlying API endpoints. Once authenticated, the attacker crafts malicious payloads containing specially formatted text designed to mimic or corrupt log entries. By supplying this input through application vectors that write to the Navigator logs, the attacker forces the logging component to append the unsanitized payload into the persistent log files.\nThe attack flow proceeds as follows: First, the remote authenticated attacker identifies an application feature or interface parameter that writes output to the Navigator log files. Second, the attacker formulates an injection payload containing newline characters (such as CR/LF) and deceptive log statements designed to spoof administrative actions, hide unauthorized activities, or introduce malformed data structures. Third, the attacker submits this payload to the target system. Fourth, the vulnerable logging component processes the input without neutralization and appends the raw payload directly into the log file. Finally, the log integrity is compromised, potentially misleading administrators or automated analysis tools reviewing the logs.\nThe affected component is the Navigator logging facility within IBM i 7.6, 7.5, 7.4, and 7.3. Privilege requirements are limited to standard remote authenticated access capable of interacting with the logging mechanisms. Network exposure depends on the accessibility of the IBM i Navigator service over the network. The post-exploitation impact is primarily concentrated on log spoofing, audit trail contamination, and potential denial of service against log analysis parsers that fail to handle malformed log entries securely."
}