CVE-2026-84414 in IBM
Summary
by MITRE • 09/29/2026
IBM i 7.6, 7.5, 7.4, and 7.3 could allow a local authenticated attacker to change the ownership of arbitrary files due to improper validation of an attacker-controlled file path.
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Analysis
by VulDB Data Team • 09/30/2026
The vulnerability identified in IBM i operating system versions 7.3 through 7.6 represents a critical failure in access control mechanisms, specifically within the handling of file operations by local authenticated users. This flaw stems from insufficient validation logic when processing user-supplied input related to file paths during ownership change requests. In standard Unix-like environments and the IBM i architecture, changing the owner of a file is typically restricted to the superuser or root due to the significant security implications involved in transferring control over sensitive system resources. However, this specific implementation flaw allows an attacker who has already gained local authentication access to bypass these restrictions by manipulating the input parameters associated with the ownership change command.
The technical core of this vulnerability lies in improper validation of an attacker-controlled file path. When a user initiates a request to alter the owner of a file, the system is expected to verify that the requesting process has sufficient privileges and that the target file resides within acceptable boundaries defined by security policies. In this case, the software fails to adequately sanitize or validate the provided path string before executing the ownership modification operation. This lack of rigorous input validation enables an attacker to specify paths outside their intended scope, potentially targeting system files, configuration data belonging to other users, or critical application binaries that are normally protected from unauthorized alteration by non-privileged accounts.
From a security impact perspective, this vulnerability facilitates privilege escalation and potential denial of service conditions. By successfully changing the ownership of arbitrary files, an attacker can gain control over resources they should not have access to. This capability allows for further exploitation steps such as injecting malicious code into legitimate applications if those applications run with elevated privileges relative to their new owner. Additionally, attackers could disrupt system stability or specific services by modifying permissions on critical configuration files, effectively rendering them unreadable or executable in unintended ways. The ability to arbitrarily change ownership undermines the principle of least privilege and compromises the integrity of the operating environment for all users sharing the same instance.
This flaw aligns with Common Weakness Enumeration (CWE) category CWE-276, which describes Incorrect Default Permissions, although it more accurately fits under CWE-284 Improper Access Control or CWE-200 Information Exposure depending on the specific outcome of the exploitation. In terms of the MITRE ATT&CK framework, this vulnerability supports techniques related to Privilege Escalation via Local Exploitation and potentially Defense Evasion if used to modify audit logs or security configurations. The attack vector is classified as local, requiring prior authentication, which limits its remote exploitability but increases the risk for multi-user systems where lateral movement between accounts becomes feasible after initial compromise.
Mitigation strategies primarily involve applying vendor-provided patches that address the input validation logic within the affected IBM i versions. Organizations should ensure their systems are updated to the latest service levels provided by IBM, which include fixes for this specific path validation issue. In environments where immediate patching is not possible, strict monitoring of file ownership changes and audit logging can help detect anomalous activities indicative of exploitation attempts. Furthermore, enforcing stricter role-based access controls and limiting local user privileges to only those necessary for their job functions can reduce the attack surface available to potential intruders who have gained initial foothold on the system. Regular security assessments focusing on input validation practices in file management utilities are also recommended to prevent similar vulnerabilities from being introduced or exploited in the future.