CVE-2026-17485 Overview
CVE-2026-17485 is an integer underflow vulnerability affecting IBM i versions 7.6, 7.5, 7.4, and 7.3. A remote, unauthenticated attacker can exploit the flaw over the network to trigger a denial of service and access sensitive information. The vulnerability is categorized under [CWE-125] (Out-of-Bounds Read) and stems from improper handling of numeric boundaries during processing. IBM has published advisory details for the affected releases.
Critical Impact
Remote attackers can cause service disruption and disclose sensitive data on affected IBM i systems without authentication or user interaction.
Affected Products
- IBM i 7.6
- IBM i 7.5
- IBM i 7.4
- IBM i 7.3
Discovery Timeline
- 2026-08-12 - CVE-2026-17485 published to NVD
- 2026-08-12 - Last updated in NVD database
Technical Details for CVE-2026-17485
Vulnerability Analysis
The vulnerability results from an integer underflow condition within IBM i. When an arithmetic operation produces a value below the minimum representable integer, the resulting wrap-around leads to incorrect memory size calculations. This condition enables an out-of-bounds read, aligned with the assigned [CWE-125] classification.
Exploitation yields two outcomes. First, the malformed read can crash the affected service, producing a denial of service. Second, the read can return adjacent memory contents, disclosing information the attacker is not authorized to view. Because the attack vector is network-based and requires no privileges or user interaction, exposed IBM i services are directly reachable by remote adversaries.
Root Cause
The root cause is an integer underflow in a length or offset computation. When attacker-controlled input drives the calculation below zero, the underflowed value is interpreted as a large unsigned quantity. Subsequent buffer access uses this incorrect length, reading past intended memory boundaries.
Attack Vector
A remote attacker sends crafted network input to a vulnerable IBM i service. The malformed request triggers the underflow, forcing the process to read out-of-bounds memory. The attacker either receives leaked memory contents in a response or crashes the service. No credentials or user interaction are required. IBM has not published exploitation code, and the vulnerability is not listed in CISA KEV at this time.
Refer to the IBM Support Page for technical specifics on the affected component.
Detection Methods for CVE-2026-17485
Indicators of Compromise
- Unexpected crashes, restarts, or ABEND messages from IBM i services exposed to the network.
- Anomalous inbound requests containing malformed length or size fields targeting IBM i ports.
- Unusual response sizes from IBM i services that may indicate memory disclosure.
Detection Strategies
- Monitor IBM i system logs and QSYSOPR message queues for repeated service faults correlated with external network activity.
- Deploy network intrusion detection signatures for malformed protocol requests targeting IBM i services.
- Baseline normal request and response sizes for exposed IBM i interfaces and alert on statistical outliers.
Monitoring Recommendations
- Forward IBM i audit journals and service logs to a centralized SIEM for correlation with network telemetry.
- Track connection sources targeting IBM i management and application ports, prioritizing untrusted networks.
- Alert on repeated connection resets or service restarts consistent with denial-of-service probing.
How to Mitigate CVE-2026-17485
Immediate Actions Required
- Apply the IBM PTFs referenced in the IBM Support Page for IBM i 7.6, 7.5, 7.4, and 7.3.
- Restrict network exposure of IBM i services to trusted management networks until patches are deployed.
- Review audit logs for evidence of denial-of-service events or anomalous requests targeting IBM i hosts.
Patch Information
IBM has published fix information on the IBM Support Page. Administrators should identify the correct PTF group for their installed release (7.6, 7.5, 7.4, or 7.3) and apply it through standard IBM i change management procedures.
Workarounds
- Enforce firewall rules that limit access to IBM i services from only authorized source addresses.
- Terminate or disable non-essential network services on IBM i partitions to reduce attack surface.
- Require VPN or bastion-host access for all administrative connectivity to IBM i systems.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
