CVE-2025-39681: Debian Linux

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: x86/cpu/hygon: Add missing resctrl_cpu_detect() in bsp_init helper Since 923f3a2b48bd ("x86/resctrl: Query LLC monitoring properties once during boot") resctrl_cpu_detect() has been moved from common CPU initialization code to the vendor-specific BSP init helper, while Hygon didn't put that call in their code. This triggers a division by zero fault during early booting stage on our machines with X86_FEATURE_CQM* supported, where get_rdt_mon_resources() tries to calculate mon_l3_config with uninitialized boot_cpu_data.x86_cache_occ_scale. Add the missing resctrl_cpu_detect() in the Hygon BSP init helper. [ bp: Massage commit message. ]

Affected products

• Debian Debian Linux: version 11.0 only
• Linux Linux Kernel: from 5.8, before 5.10.242 (fixed in 5.10.242); from 5.11, before 5.15.190 (fixed in 5.15.190); from 5.16, before 6.1.149 (fixed in 6.1.149); from 6.2, before 6.6.103 (fixed in 6.6.103); from 6.7, before 6.12.44 (fixed in 6.12.44); from 6.13, before 6.16.4 (fixed in 6.16.4); …

Published 2025-09-05. Last modified 2026-07-14.