CVE-2026-17259: CWE-121 Stack-based Buffer Overflow

This vulnerability is a stack-based buffer overflow (CWE-121) in IBM i operating system versions 7.3 through 7.6. An attacker with valid authentication credentials can exploit this flaw remotely to trigger a denial of service by causing the affected process or system to crash. The CVSS 3.1 base score is 4.3, reflecting a medium severity with network attack vector, low attack complexity, and no user interaction required. There is no indication of confidentiality or integrity impact. No official remediation or patch information is currently available from the vendor, and no known exploits are reported in the wild.

The primary impact is denial of service, which can cause system or service unavailability. There is no impact on confidentiality or integrity according to the CVSS vector. The vulnerability requires the attacker to be authenticated, limiting the attack surface to authorized users.

Patch status is not yet confirmed — check the IBM vendor advisory for current remediation guidance. Until a fix is available, limit access to trusted authenticated users and monitor for unusual system crashes or disruptions related to IBM i services.