CVE-2026-97876Bypass of GRUB lockdown restriction in Secure Boot mode via serial command MMIO base address
Updated under an hour ago ()
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It affects GNU grub2. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 6.4 MEDIUM (v3.1, CNA)CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-822
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- canonical
- NVD analysis
- Awaiting Analysis
- Record last updated
- Oct 2, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
GNU grub2 gnu:grub2 (from the name) | from 2.12 before 2.16 | CNA record |
References
- https://www.openwall.com/lists/oss-security/2026/09/13/5mailing-list
- https://gitlab.freedesktop.org/gnu-grub/grub/-/commit/26beaa3b2720fefdc4d04c1ae209b776fe6848d6patch
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.