cbcvebase.
CVE-2025-21872
published 2025-03-27

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…

PriorityP419medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.19%
9.3th percentile
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: ? __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 ---[ 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.

Affected

19 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 5.10.237-1 (bullseye)linux 5.10.237-1 (bullseye)
linuxlinux
linuxlinux>= 58c909022a5a56cd1d9e89c8c5461fd1f6a27bb5 < 46c0454ffb78ce9d3355a3cccac86383ea8ddd5546c0454ffb78ce9d3355a3cccac86383ea8ddd55
linuxlinux>= 58c909022a5a56cd1d9e89c8c5461fd1f6a27bb5 < ea3f0b362dfe4ef885ef812bfaf4088176422c91ea3f0b362dfe4ef885ef812bfaf4088176422c91
linuxlinux>= 58c909022a5a56cd1d9e89c8c5461fd1f6a27bb5 < 65f4aebb8127708ba668dd938e83b8558abfc5cd65f4aebb8127708ba668dd938e83b8558abfc5cd
linuxlinux>= 58c909022a5a56cd1d9e89c8c5461fd1f6a27bb5 < 97bd560b6cc4c26386a53b4881bf03e96f9ba03a97bd560b6cc4c26386a53b4881bf03e96f9ba03a
linuxlinux>= 58c909022a5a56cd1d9e89c8c5461fd1f6a27bb5 < 2b90e7ace79774a3540ce569e000388f8d22c9e02b90e7ace79774a3540ce569e000388f8d22c9e0
linuxlinux_kernel
linuxlinux_kernel>= 0 < 5.10.237-15.10.237-1
linuxlinux_kernel>= 0 < 6.12.19-16.12.19-1
linuxlinux_kernel>= 0 < 6.12.19-16.12.19-1
linuxlinux_kernel>= 0 < 6.8.0-84.846.8.0-84.84
linuxlinux_kernel>= 5.10 < 5.10.2355.10.235
linuxlinux_kernel>= 5.11 < 6.6.836.6.83
linuxlinux_kernel>= 6.13 < 6.13.66.13.6
linuxlinux_kernel>= 6.7 < 6.12.186.12.18
msrccbl2_kernel_5.15.186.1-1_on_cbl_mariner_2.0
msrccbl2_kernel_5.15.200.1-1_on_cbl_mariner_2.0
msrccbl2_kernel_5.15.202.1-1_on_cbl_mariner_2.0

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv5.5MEDIUM
vendor_debian5.5MEDIUM
vendor_msrc5.5MEDIUM
vendor_redhat5.5MEDIUM
vendor_ubuntu5.5MEDIUM
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