CVE-2025-39681

x86/cpu/hygon: Add missing resctrl_cpu_detect() in bsp_init helper

MEDIUM

5.5

CVSS Score

Published: September 5, 2025 at 05:20 PM UTC

Updated: October 19, 2026 at 09:10 PM UTC

6 products affected across 3 vendorsLinux KernelDebian LinuxSIMATIC S7-1500 CPU 1518-4 Pn /dp MFP Firmware

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Severity

MEDIUM5.5

Exploit prediction

EPSS 0.2%

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. ]

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Debian Linux · Debiandrupal

95%

11.0

Linux Kernel · Linux

95%

5.11 ≤ v < 5.15.1905.16 ≤ v < 6.1.1495.8 ≤ v < 5.10.2426.13 ≤ v < 6.16.46.2 ≤ v < 6.6.1036.7 ≤ v < 6.12.446.17 6.17 rc1 6.17 rc2923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9

Vendor states this is fixed in 62f12cde10118253348a7540e85606869bd69432 (fixed)

Vendor states this is fixed in 7207923d8453ebfb35667c1736169f2dd796772e (fixed)

Vendor states this is fixed in 873f32201df8876bdb2563e3187e79149427cab4 (fixed)

Vendor states this is fixed in a9e5924daa954c9f585c1ca00358afe71d6781c4 (fixed)

Vendor states this is fixed in d23264c257a70dbe021b43b3bc2ee16134cd2c69 (fixed)

Vendor states this is fixed in d8df126349dad855cdfedd6bbf315bad2e901c2f (fixed)

Vendor states this is fixed in fb81222c1559f89bfe3aa1010f6d112531d55353 (fixed)

Vendor states this is fixed in 5.10.242 (unaffected)

Vendor states this is fixed in 5.15.190 (unaffected)

Vendor states this is fixed in 5.8 (unaffected)

Vendor states this is fixed in 6.1.149 (unaffected)

Vendor states this is fixed in 6.12.44 (unaffected)