Microsoft AI Exposes 21-Year-Old Linux Kernel Bug Among 59 Security Issues Reported to Maintainers

What happened

One full-time researcher and one intern scanned selected kernel subsystems, including networking, filesystems and security modules, from late May to mid-June 2026. AI-driven scanning system, codenamed MDASH, to find 59 security issues in the Linux kernel. Microsoft is a software and software development company based in Redmond.

One of them, a cls_u32 shift-out-of-bounds flaw tracked as CVE-2026-74544 (the public catalogue number for a specific software flaw), had gone unnoticed for at least 21 years.