CVE-2025-21872

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2025-21872
In the Linux kernel, the following vulnerability has been resolved: efi: Don't map the entire mokvar table to determine its size Currently, when validating the mokvar table, we (re)map the entire table on each iteration of the loop, adding space as we discover new entries. If the table grows over a certain size, this fails due to limitations of early_memmap(), and we get a failure and traceback: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 0 at mm/early_ioremap.c:139 __early_ioremap+0xef/0x220 ... Call Trace: <TASK> ? __early_ioremap+0xef/0x220 ? __warn.cold+0x93/0xfa ? __early_ioremap+0xef/0x220 ? report_bug+0xff/0x140 ? early_fixup_exception+0x5d/0xb0 ? early_idt_handler_common+0x2f/0x3a ? __early_ioremap+0xef/0x220 ? efi_mokvar_table_init+0xce/0x1d0 ? setup_arch+0x864/0xc10 ? start_kernel+0x6b/0xa10 ? x86_64_start_reservations+0x24/0x30 ? x86_64_start_kernel+0xed/0xf0 ? common_startup_64+0x13e/0x141 </TASK> ---[ end trace 0000000000000000 ]--- mokvar: Failed to map EFI MOKvar config table pa=0x7c4c3000, size=265187. Mapping the entire structure isn't actually necessary, as we don't ever need more than one entry header mapped at once. Changes efi_mokvar_table_init() to only map each entry header, not the entire table, when determining the table size. Since we're not mapping any data past the variable name, it also changes the code to enforce that each variable name is NUL terminated, rather than attempting to verify it in place.

5.5 /10

CVSS v3 : MEDIUM

V3 Legend

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References
Link Resource
https://git.kernel.org/stable/c/2b90e7ace79774a3540ce569e000388f8d22c9e0 Patch
https://git.kernel.org/stable/c/46c0454ffb78ce9d3355a3cccac86383ea8ddd55 Patch
https://git.kernel.org/stable/c/65f4aebb8127708ba668dd938e83b8558abfc5cd Patch
https://git.kernel.org/stable/c/97bd560b6cc4c26386a53b4881bf03e96f9ba03a Patch
https://git.kernel.org/stable/c/ea3f0b362dfe4ef885ef812bfaf4088176422c91 Patch
Configurations

Configuration 1 (hide)

OR cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc4:*:*:*:*:*:*
History

30 Oct 2025, 16:19

Type Values Removed Values Added
CPE cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Summary
  • (es) En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: efi: No asigne toda la tabla mokvar para determinar su tamaño Actualmente, al validar la tabla mokvar, (re)asignamos la tabla completa en cada iteración del bucle, agregando espacio a medida que descubrimos nuevas entradas. Si la tabla crece por encima de cierto tamaño, esto falla debido a las limitaciones de early_memmap(), y obtenemos un error y seguimiento: ------------[ cortar aquí ]------------ ADVERTENCIA: CPU: 0 PID: 0 en mm/early_ioremap.c:139 __early_ioremap+0xef/0x220 ... Seguimiento de llamada: ? __early_ioremap+0xef/0x220 ? __warn.cold+0x93/0xfa ? __early_ioremap+0xef/0x220 ? report_bug+0xff/0x140 ? early_fixup_exception+0x5d/0xb0 ? early_idt_handler_common+0x2f/0x3a ? __early_ioremap+0xef/0x220 ? efi_mokvar_table_init+0xce/0x1d0 ? setup_arch+0x864/0xc10 ? start_kernel+0x6b/0xa10 ? x86_64_start_reservations+0x24/0x30 ? x86_64_start_kernel+0xed/0xf0 ? common_startup_64+0x13e/0x141 ---[ fin del seguimiento 0000000000000000 ]--- mokvar: Error al asignar la tabla de configuración EFI MOKvar pa=0x7c4c3000, tamaño=265187. No es necesario asignar toda la estructura, ya que no necesitamos asignar más de un encabezado de entrada a la vez. Se modifica efi_mokvar_table_init() para que solo asigne cada encabezado de entrada, no toda la tabla, al determinar el tamaño de la tabla. Dado que no se asignan datos más allá del nombre de la variable, también se modifica el código para que cada nombre de variable termine en NUL, en lugar de intentar verificarlo en su lugar.
CVSS v2 : unknown
v3 : unknown 		v2 : unknown
v3 : 5.5
CWE NVD-CWE-noinfo
First Time Linux linux Kernel
Linux
References () https://git.kernel.org/stable/c/2b90e7ace79774a3540ce569e000388f8d22c9e0 - () https://git.kernel.org/stable/c/2b90e7ace79774a3540ce569e000388f8d22c9e0 - Patch
References () https://git.kernel.org/stable/c/46c0454ffb78ce9d3355a3cccac86383ea8ddd55 - () https://git.kernel.org/stable/c/46c0454ffb78ce9d3355a3cccac86383ea8ddd55 - Patch
References () https://git.kernel.org/stable/c/65f4aebb8127708ba668dd938e83b8558abfc5cd - () https://git.kernel.org/stable/c/65f4aebb8127708ba668dd938e83b8558abfc5cd - Patch
References () https://git.kernel.org/stable/c/97bd560b6cc4c26386a53b4881bf03e96f9ba03a - () https://git.kernel.org/stable/c/97bd560b6cc4c26386a53b4881bf03e96f9ba03a - Patch
References () https://git.kernel.org/stable/c/ea3f0b362dfe4ef885ef812bfaf4088176422c91 - () https://git.kernel.org/stable/c/ea3f0b362dfe4ef885ef812bfaf4088176422c91 - Patch

27 Mar 2025, 15:15

Type Values Removed Values Added
New CVE
Information

Published : 2025-03-27 15:15

Updated : 2025-10-30 16:19

NVD link : CVE-2025-21872

Mitre link : CVE-2025-21872

CVE.ORG link : CVE-2025-21872

JSON object : View

Products Affected

linux

  • linux_kernel
CWE
NVD-CWE-noinfo