CVE-2023-52504: Linux Kernel

High severity, CVSS 7.1. EPSS: 0.3% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: x86/alternatives: Disable KASAN in apply_alternatives() Fei has reported that KASAN triggers during apply_alternatives() on a 5-level paging machine: BUG: KASAN: out-of-bounds in rcu_is_watching() Read of size 4 at addr ff110003ee6419a0 by task swapper/0/0 ... __asan_load4() rcu_is_watching() trace_hardirqs_on() text_poke_early() apply_alternatives() ... On machines with 5-level paging, cpu_feature_enabled(X86_FEATURE_LA57) gets patched. It includes KASAN code, where KASAN_SHADOW_START depends on __VIRTUAL_MASK_SHIFT, which is defined with cpu_feature_enabled(). KASAN gets confused when apply_alternatives() patches the KASAN_SHADOW_START users. A test patch that makes KASAN_SHADOW_START static, by replacing __VIRTUAL_MASK_SHIFT with 56, works around the issue. Fix it for real by disabling KASAN while the kernel is patching alternatives. [ mingo: updated the changelog ]

Affected products

• Linux Linux Kernel: from 4.17, before 4.19.297 (fixed in 4.19.297); from 4.20, before 5.4.270 (fixed in 5.4.270); from 5.5, before 5.10.199 (fixed in 5.10.199); from 5.11, before 5.15.136 (fixed in 5.15.136); from 5.16, before 6.1.59 (fixed in 6.1.59); from 6.2, before 6.5.8 (fixed in 6.5.8); …

Published 2024-03-02. Last modified 2026-06-17.