Description

IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote authenticated attacker to cause a denial of service due to improper neutralization of special elements in an OS command.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.1",
  "pubDate": "2026-08-12T18:17:26.190Z",
  "pubdate": "2026-08-12T18:17:26.190Z",
  "executiveSummary": "This vulnerability involves an improper neutralization of special elements in an operating system command within IBM i. Specifically, the flaw allows a remote authenticated attacker to execute unauthorized operating system commands, resulting in a denial of service condition affecting system availability. The affected products include IBM i versions 7.6, 7.5, 7.4, and 7.3. The primary risk implication is the degradation or complete disruption of system operations, preventing legitimate users from accessing critical services. Exploitation of this vulnerability requires the attacker to possess valid authentication credentials to the target system. The attack vector involves submitting maliciously crafted inputs containing special command-line elements that are improperly sanitized by the vulnerable component. Once processed, these inputs manipulate the underlying command execution flow, forcing the operating system to enter an unstable or unresponsive state. Remediation requires applying official vendor-supplied patches or updates as soon as they become available, along with enforcing strict access controls and input validation mechanisms to limit the risk of authenticated misuse.",
  "technicalDetails": "The root cause of this vulnerability stems from the inadequate sanitization and filtering of user-supplied input before it is passed to the underlying operating system shell or command interpreter. This represents a classic OS command injection flaw where special characters or command separators are not properly neutralized.\nThe affected components reside within IBM i versions 7.6, 7.5, 7.4, and 7.3, where certain interfaces or functions fail to validate parameters adequately before executing system-level operations.\nTo exploit this vulnerability, an attacker must first obtain valid authentication credentials to establish an authorized session with the target IBM i system. While network exposure depends on the specific service configuration, the attack can be executed remotely if the vulnerable interface is accessible over the network.\nThe attack flow proceeds as follows: First, the authenticated attacker identifies an input vector or parameter that is processed by a vulnerable backend function executing OS commands. Second, the attacker crafts a malicious payload containing specially engineered shell metacharacters or command delimiters designed to break out of the intended argument context and append arbitrary commands. Third, the attacker transmits this payload to the target system through the vulnerable interface. Fourth, the application processes the input and concatenates it directly into a system command string without proper neutralization. Finally, the operating system executes the resulting concatenated command string.\nThe payload behavior in this scenario is specifically engineered to exhaust system resources, terminate critical system processes, or induce a kernel-level hang, thereby causing a denial of service. The post-exploitation impact is limited to availability disruption, as the primary manifestation of the attack is system instability or unresponsiveness rather than arbitrary code execution with elevated privileges or data exfiltration, though the underlying injection primitive theoretically permits arbitrary command execution within the context of the running service."
}