CVE-2020-25632

Code execution via dependency-unaware rmmod unloading

Published Mar 3, 2021 · Updated Aug 4, 2024

Use-after-free in GNU GRUB before 2.06 allows local users to execute arbitrary code or bypass UEFI Secure Boot through rmmod. Repeated rmmod commands always decrement a module's reference count, allowing a dependency to unload while a loaded module still uses it. Exploitation requires local administrative privileges or physical access and can compromise the boot trust boundary or crash the bootloader.

CVSS severity7.5
High
EPSS probability1.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in GNU GRUB before 2.06 allows local users to execute arbitrary code or bypass UEFI Secure Boot through rmmod. Repeated rmmod commands always decrement a module's reference count, allowing a dependency to unload while a loaded module still uses it. Exploitation requires local administrative privileges or physical access and can compromise the boot trust boundary or crash the bootloader.

The record

CVE
CVE-2020-25632
Published
Mar 3, 2021
Updated
Aug 4, 2024
Vendor
The GnuPG Project
Product
GNU GRUB
Classifications
CWE-416, T1542.003
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Mar 3, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=grub 2.06

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The GnuPG Project · GNU GRUBversion=grub 2.06

Published CVSS scores

7.5GRUB coordinated disclosureCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1542.003Bootkit

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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