CVE-2025-21872
Estado: ModificadaMedia (5.5)—
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:
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.
Leer descripción completaMostrar menos
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.
Detalles técnicos trazas, registros y código del informe original
------------[ 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.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Puntuación base: 5.5
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.20%
- Percentil entre todas las CVEs puntuadas: 9
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
CWE
- NVD-CWE-noinfo
Referencias
- https://git.kernel.org/stable/c/2b90e7ace79774a3540ce569e000388f8d22c9e0
- https://git.kernel.org/stable/c/46c0454ffb78ce9d3355a3cccac86383ea8ddd55
- https://git.kernel.org/stable/c/65f4aebb8127708ba668dd938e83b8558abfc5cd
- https://git.kernel.org/stable/c/97bd560b6cc4c26386a53b4881bf03e96f9ba03a
- https://git.kernel.org/stable/c/ea3f0b362dfe4ef885ef812bfaf4088176422c91
- https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html
JSON original (NVD)
Mostrar
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nefi: Don't map the entire mokvar table to determine its size\n\nCurrently, when validating the mokvar table, we (re)map the entire table\non each iteration of the loop, adding space as we discover new entries.\nIf the table grows over a certain size, this fails due to limitations of\nearly_memmap(), and we get a failure and traceback:\n\n ------------[ cut here ]------------\n WARNING: CPU: 0 PID: 0 at mm/early_ioremap.c:139 __early_ioremap+0xef/0x220\n ...\n Call Trace:\n <TASK>\n ? __early_ioremap+0xef/0x220\n ? __warn.cold+0x93/0xfa\n ? __early_ioremap+0xef/0x220\n ? report_bug+0xff/0x140\n ? early_fixup_exception+0x5d/0xb0\n ? early_idt_handler_common+0x2f/0x3a\n ? __early_ioremap+0xef/0x220\n ? efi_mokvar_table_init+0xce/0x1d0\n ? setup_arch+0x864/0xc10\n ? start_kernel+0x6b/0xa10\n ? x86_64_start_reservations+0x24/0x30\n ? x86_64_start_kernel+0xed/0xf0\n ? common_startup_64+0x13e/0x141\n </TASK>\n ---[ end trace 0000000000000000 ]---\n mokvar: Failed to map EFI MOKvar config table pa=0x7c4c3000, size=265187.\n\nMapping the entire structure isn't actually necessary, as we don't ever\nneed more than one entry header mapped at once.\n\nChanges efi_mokvar_table_init() to only map each entry header, not the\nentire table, when determining the table size. Since we're not mapping\nany data past the variable name, it also changes the code to enforce\nthat each variable name is NUL terminated, rather than attempting to\nverify it in place."
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{
"lang": "es",
"value": "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."
}
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"lastModified": "2026-06-17T08:44:30.137",
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