CVE-2021-3418

low-risk

Published 2021-03-15

If certificates that signed grub are installed into db, grub can be booted directly. It will then boot any kernel without signature validation. The booted kernel will think it was booted in secureboot mode and will implement lockdown, yet it could have been tampered. This flaw is a reintroduction of CVE-2020-15705 and only affects grub2 versions prior to 2.06 and upstream and distributions using the shim_lock mechanism.

Do I need to act?

0.07% chance of exploitation

EPSS score — low exploit probability

Not on CISA KEV list

No confirmed active exploitation reported to CISA

Patch status unknown

Check vendor advisories for fix availability and mitigation guidance

CVSS 6.4/10 Medium

LOCAL / HIGH complexity

Affected Products (1)

Grub2

Affected Vendors

Gnu

References (2)

Issue Tracking https://bugzilla.redhat.com/show_bug.cgi?id=1933757

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low-risk

Severity 17/34 · Moderate

Exploitability 0/34 · Minimal

Exposure 5/34 · Minimal