CVE-2025-39681

MEDIUM

Linux Kernel - Division by Zero via Uninitialized boot_cpu_data.x86_cache_occ_scale

Title source: llm
STIX 2.1

Description

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. ]

Scores

CVSS v3 5.5
EPSS 0.0002
EPSS Percentile 6.6%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Details

Status published
Products (25)
debian/debian_linux 11.0
linux/Kernel 5.11.0 - 5.15.190linux
linux/Kernel 5.16.0 - 6.1.149linux
linux/Kernel 5.8.0 - 5.10.242linux
linux/Kernel 6.13.0 - 6.16.4linux
linux/Kernel 6.2.0 - 6.6.103linux
linux/Kernel 6.7.0 - 6.12.44linux
Linux/Linux < 5.8
Linux/Linux 5.10.242 - 5.10.*
Linux/Linux 5.15.190 - 5.15.*
... and 15 more
Published Sep 05, 2025
Tracked Since Feb 18, 2026