CVE-2026-97876
MEDIUMDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
Low risk: more likely to be exploited than 1% of all known CVEs.
References
Related Vulnerabilities
Other CWE-822 (Untrusted Pointer Dereference) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2023-21768 | High | 7.8 | 65% | - | Fix |
| CVE-2024-21338 | High | 7.8 | 60% | KEV + Ransom | Fix |
| CVE-2024-35250 | High | 7.8 | 25% | KEV | Fix |
| CVE-2023-29360 | High | 8.4 | 22% | KEV | Fix |
| CVE-2023-36033 | High | 7.8 | 11% | KEV | Fix |
| CVE-2025-50165 | Critical | 9.8 | 10% | - | Fix |
Common questions
How do I fix CVE-2026-97876?
Upgrade grub2 on debian unstable to 2.14-4 or later.
Is CVE-2026-97876 being actively exploited?
Not that we know of. CVE-2026-97876 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.11% is the estimated probability that it will be exploited in the next 30 days. That is higher than 1% of all scored CVEs.
How severe is CVE-2026-97876?
CVE-2026-97876 has a CVSS v3 base score of 6.4, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-97876 affect?
Published advisories record a fix for grub2 (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-10-02.