6.4

CVE-2026-97876

Bypass of GRUB lockdown restriction in Secure Boot mode via serial command MMIO base address

A local attacker with control over GRUB's configuration can bypass lockdown restrictions when booting with Secure Boot and load an unsigned GRUB module, while GRUB continues to report lockdown is enabled.




The vulnerability is caused by insufficient validation of the MMIO base address passed to the GRUB serial command. GRUB does not validate that the base address corresponds to a UART device, rather than being an arbitrary memory address. This allows an attacker to trick GRUB into writing non-arbitrary data at an attacker-controlled address, including resetting the grub_file_verifiers list in a way that disables the subsequent verification of loaded modules.
Daten sind bereitgestellt durch das CVE Programm von einer CVE Numbering Authority (CNA) (Unstrukturiert).
HerstellerGNU
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Produkt grub2
Default Statusunaffected
Version 2.12
Version < 2.16
Status affected
VulnDex Vulnerability Enrichment
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.12% 0.014
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
Canonical 6.4 0.5 5.9
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
CWE-822 Untrusted Pointer Dereference

The product obtains a value from an untrusted source, converts this value to a pointer, and dereferences the resulting pointer.

https://www.openwall.com/lists/oss-security/2026/09/13/5
https://gitlab.freedesktop.org/gnu-grub/grub/-/commit/26beaa3b2720fefdc4d04c1ae209b776fe6848d6