CVE-2026-91759 is an out-of-bounds write vulnerability in Hitachi Dynamic Link Manager for Linux versions from 7.5.0-00 up to but not including 9.0.5-00. This flaw allows an attacker with local privileges to write outside the intended memory bounds, potentially leading to complete system compromise. The vulnerability has been assigned a high severity with a CVSS score of 7.8. A fix is available in version 9.0.5-00.