CVE-2026-18099 in IBM
Summary
by MITRE • 08/12/2026
IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote authenticated attacker to execute arbitrary script code due to improper neutralization of user-controlled input.
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Analysis
by VulDB Data Team • 08/12/2026
This vulnerability affects IBM i operating systems versions 7.6, 7.5, 7.4, and 7.3, presenting a critical security risk that enables remote authenticated attackers to execute arbitrary script code. The flaw stems from inadequate sanitization of user-supplied input within the system's processing mechanisms, creating a path for malicious actors to inject and subsequently execute harmful scripts. The improper neutralization of input represents a fundamental breakdown in the system's security controls, allowing attackers who have already established authentication credentials to escalate their privileges through code execution.
The technical implementation of this vulnerability aligns with common web application security flaws classified under CWE-79 - Improper Neutralization of Input During Web Page Generation. This weakness occurs when applications fail to properly validate or sanitize user input before incorporating it into dynamically generated content, particularly within web interfaces or script contexts. The vulnerability exists in the input processing layer where user-controlled data flows through system components without adequate filtering or encoding mechanisms that would prevent malicious code injection.
From an operational perspective, this vulnerability provides attackers with a potent vector for compromising IBM i environments, potentially leading to complete system takeover or unauthorized access to sensitive data. The authenticated nature of the attack means that adversaries must first establish legitimate credentials, but once inside the system, they can leverage this flaw to execute arbitrary commands and scripts without additional authentication requirements. This creates a significant risk for organizations using these operating systems in production environments where business-critical applications and data reside.
The impact extends beyond simple code execution as attackers could potentially access the underlying system resources, modify or delete sensitive data, establish persistent backdoors, or use the compromised system as a launch point for further attacks against networked systems. Organizations utilizing these IBM i versions face potential regulatory compliance violations, data breaches, and operational disruptions that could result in substantial financial losses and reputational damage.
Mitigation strategies should focus on implementing comprehensive input validation mechanisms across all user-facing interfaces and application components within the IBM i environment. Organizations must ensure that all user-supplied data undergoes strict sanitization before processing, including proper encoding of special characters and implementation of whitelisting approaches for acceptable input formats. System administrators should apply available security patches from IBM as soon as they become available, while also implementing network segmentation and access controls to limit the potential impact of successful exploitation attempts. Regular security assessments and monitoring of system logs for anomalous script execution patterns can help detect and respond to exploitation attempts effectively, aligning with defensive techniques documented in the MITRE ATT&CK framework under the execution and privilege escalation domains.