CVE-2026-53343

Summary

In the Linux kernel, the following vulnerability has been resolved:

ARM: 9475/1: entry: use byte load for KASAN VMAP stack shadow

Commit 44e9a3bb76e5 ("ARM: 9430/1: entry: Do a dummy read from VMAP shadow") added a dummy read from the KASAN VMAP stack shadow in __switch_to(). The read uses ldr, but the KASAN shadow address is byte-granular and is not guaranteed to be word aligned.

ARMv5 faults unaligned word loads. With CONFIG_KASAN_VMALLOC and CONFIG_VMAP_STACK enabled, ARM926/VersatilePB crashes in __switch_to() with an alignment exception before reaching init.

Use ldrb for the dummy shadow access. The code only needs to fault in the shadow mapping if the stack shadow is missing, so a byte load is sufficient and matches the granularity of KASAN shadow memory.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux8fe148d39c127de3fb78dfa6da95a3608dfda454 < c0b8c148a7754826156993ed6442d31536ec86b4affected
LinuxLinuxef21187c0672a2b2cbec44f33bab9ec47d5c277c < c2e3aadc8fef7da068490597fc5582f8f362aeb2affected
LinuxLinuxc86d26b4b089ca294b3b7d915a7da61edb77935f < c74990828d3c486ee44aaa68240eb3abff289d1caffected
LinuxLinux44e9a3bb76e5f2eecd374c8176b2c5163c8bb2e2 < 517720913bd3c17a52cd55a740064f68455ab88eaffected
LinuxLinux44e9a3bb76e5f2eecd374c8176b2c5163c8bb2e2 < 2a4dc9a0ac3326e79fb58fdaae724b92127709a9affected
LinuxLinux44e9a3bb76e5f2eecd374c8176b2c5163c8bb2e2 < 77a1f6883dc6e837bb2cb30b9b02e2f94338e2c6affected
LinuxLinux6.1.120 < 6.1.176affected
LinuxLinux6.6.64 < 6.6.143affected
LinuxLinux6.12.4 < 6.12.94affected
LinuxLinux6.13affected
LinuxLinux0 < 6.13unaffected
LinuxLinux6.1.176 <= 6.1.*unaffected
LinuxLinux6.6.143 <= 6.6.*unaffected
LinuxLinux6.12.94 <= 6.12.*unaffected
LinuxLinux6.18.36 <= 6.18.*unaffected
LinuxLinux7.0.13 <= 7.0.*unaffected
LinuxLinux7.1 <= *unaffected

Weaknesses

References