Bug 2414477 (CVE-2025-40157)

Summary: CVE-2025-40157 kernel: Linux kernel: Denial of service in i10nm_edac driver due to disabled memory controller
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in the Linux kernel's i10nm_edac driver. A local user with elevated privileges could trigger a denial of service when the driver is loaded on systems where a memory controller is disabled by the BIOS due to unpopulated memory modules (DIMMs). This specific condition causes a shift-out-of-bounds error, leading to a system crash and making the system unavailable.
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Description OSIDB Bzimport 2025-11-12 11:02:22 UTC 
In the Linux kernel, the following vulnerability has been resolved:

EDAC/i10nm: Skip DIMM enumeration on a disabled memory controller

When loading the i10nm_edac driver on some Intel Granite Rapids servers,
a call trace may appear as follows:

  UBSAN: shift-out-of-bounds in drivers/edac/skx_common.c:453:16
  shift exponent -66 is negative
  ...
  __ubsan_handle_shift_out_of_bounds+0x1e3/0x390
  skx_get_dimm_info.cold+0x47/0xd40 [skx_edac_common]
  i10nm_get_dimm_config+0x23e/0x390 [i10nm_edac]
  skx_register_mci+0x159/0x220 [skx_edac_common]
  i10nm_init+0xcb0/0x1ff0 [i10nm_edac]
  ...

This occurs because some BIOS may disable a memory controller if there
aren't any memory DIMMs populated on this memory controller. The DIMMMTR
register of this disabled memory controller contains the invalid value
~0, resulting in the call trace above.

Fix this call trace by skipping DIMM enumeration on a disabled memory
controller.
Comment 1 Alexander B 2025-11-13 16:11:48 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025111258-CVE-2025-40157-d08c@gregkh/T