External risk intelligence

IBM i Security Bypass Vulnerability Allows Unauthorized Access.

CVE advisorySeverity: CRITICAL (CVSS 10.0)

CVE-2026-18193

IBM i is an enterprise operating system typically deployed within protected internal networks to support business applications and database services. While network-reachable in some environments, it is not designed to be directly exposed to the public internet, and public-facing configurations are uncommon.

Ibm I

7.37.47.57.6

Halo Surface Signal: 2 out of 5 — less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

IBM i systems may have a vulnerability that could allow unauthorized access and bypass security measures due to improper handling of user-supplied addresses. This issue affects multiple versions of the IBM i operating system.

Remote attackers could bypass security controls.
Critical vulnerability could impact system integrity.
Confirm relevance and exposure to IBM i systems.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by sending specially crafted requests over the network, as no authentication or user interaction is required. The vulnerability stems from the system's failure to properly validate user-supplied addresses, which could allow an attacker to bypass existing security measures. Successful exploitation could lead to significant data compromise and unauthorized system modifications.

Requires network access.
Triggers on invalid address validation.
Risk of security bypass.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability in IBM i could allow an unauthenticated remote attacker to bypass security restrictions when interacting with specific system functions, potentially leading to unauthorized access to sensitive system data or unexpected service behavior. The improper validation of user-controlled addresses is the root cause, affecting the integrity and confidentiality of the system.

System data and service integrity at risk.
Bypass security restrictions via network.
Unauthorized system access possible.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability impacts IBM i systems, likely managed by infrastructure or platform teams, and potentially requiring coordination with application owners and the vendor. The initial practical step is to identify all instances of the affected IBM i versions, confirm their network reachability and business criticality, and then assign ownership for remediation planning.

Infrastructure or Platform Teams own remediation.
Verify network exposure and business criticality.
Plan remediation based on identified risk.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is IBM i?

IBM i is a highly integrated, secure operating system designed for enterprise environments. It serves as a robust platform for running core business applications, managing large-scale databases, and executing critical transaction processing, typically within dedicated server infrastructures.

What does CWE-269 mean for CVE-2026-18193?

This CVE involves Improper Privilege Management. In this context, it means the system fails to correctly verify the origin or legitimacy of user-supplied addresses, allowing a remote user to bypass built-in security barriers and perform actions they should not be authorized to take.

How can an attacker trigger this vulnerability?

An attacker triggers this by sending specially crafted network requests that target the flawed address validation logic. Crucially, this does not require any existing user credentials or interaction; however, normal, valid administrative or user traffic that adheres to expected address formats does not trigger the flaw.

Is my IBM i system at risk?

According to Halo Surface Signal, these systems are typically deployed in protected internal networks, making direct internet exposure uncommon. However, you should evaluate if your specific instance is reachable from untrusted network segments, as this increases the likelihood of unauthorized interaction.

What steps should I take to manage this risk?

Begin by inventorying your environment to locate all instances of IBM i versions 7.3 through 7.6. Once identified, verify their current network accessibility and prioritize those that have broader connectivity. Consult official IBM support resources to coordinate patching with your infrastructure and application teams.

References

www.ibm.com/support/pages/node/7283283

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.