CVE-2025-21872
CVE-2025-21872CVE-2025-21872
linux / linux_kernel
Description
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>
---[
Scoring
| CVSS | 5.5 () |
| Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
| Last modified | 2026-10-30 |