Linux Kernel EUVD-2026-27604

Upgrade to Linux kernel 6.19.14 or 7.0 or later, which contain upstream fixes removing the redundant ida_free call in the hv_pci_probe error path (commits 21bc8e0ba5c2 for stable, b6422dff0e51 for mainline). For enterprise distributions, apply vendor-provided security updates incorporating these commits: check with Red Hat, Ubuntu, SUSE, or Debian for backported patches to supported kernel branches. If immediate patching is not feasible, apply these compensating controls with noted trade-offs: (1) Disable PCI hot-plug in Hyper-V guest configuration to reduce probe failure scenarios, though this limits dynamic hardware management; (2) Monitor kernel logs for ida_free warnings and reboot affected VMs proactively, accepting potential service interruption to prevent allocator corruption accumulation; (3) Restrict local user access on Hyper-V Linux guests to trusted administrators only, reducing attack surface but not eliminating risk from compromised low-privilege accounts. None of these workarounds fully mitigate the vulnerability, so kernel upgrade remains the definitive remediation. Patch advisory URLs: https://git.kernel.org/stable/c/21bc8e0ba5c2a081b0a2808c976d4c9dbddf1e48 and https://git.kernel.org/stable/c/b6422dff0e518245019233432b6bccfc30b73e2f.