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.
No advisories yet.
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
Sat, 03 Oct 2026 06:30:00 +0000
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|---|---|---|
| Metrics |
ssvc
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Sat, 03 Oct 2026 00:30:00 +0000
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| References |
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| Metrics |
threat_severity
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threat_severity
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Fri, 02 Oct 2026 11:45:00 +0000
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| First Time appeared |
Gnu
Gnu grub2 |
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| Vendors & Products |
Gnu
Gnu grub2 |
Fri, 02 Oct 2026 10:45:00 +0000
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| Description | 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. | |
| Title | Bypass of GRUB lockdown restriction in Secure Boot mode via serial command MMIO base address | |
| Weaknesses | CWE-822 | |
| References |
| |
| Metrics |
cvssV3_1
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Projects
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Status: PUBLISHED
Assigner: canonical
Published:
Updated: 2026-10-02T17:45:06.705Z
Reserved: 2026-09-25T08:49:34.867Z
Link: CVE-2026-97876
Updated: 2026-10-02T17:44:59.967Z
Status : Awaiting Analysis
Published: 2026-10-02T11:17:39.727
Modified: 2026-10-02T18:44:11.270
Link: CVE-2026-97876
OpenCVE Enrichment
Updated: 2026-10-02T12:00:15Z