CVE-2025-0678

Secure Boot bypass via squash4 allocation overflow

Published Mar 3, 2025 · Updated Jun 29, 2026

Heap-based out-of-bounds write in GNU GRUB 2.12 and earlier allows local users to execute code via a crafted squash4 filesystem. The squash4 direct_read() path multiplies attacker-controlled filesystem geometry values without complete overflow checks, so grub_malloc() allocates an undersized buffer before data is copied into it. Exploitation requires access that causes GRUB to read the crafted filesystem; successful corruption executes code in the bootloader and bypasses Secure Boot protections.

CVSS severity7.8
High
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based out-of-bounds write in GNU GRUB 2.12 and earlier allows local users to execute code via a crafted squash4 filesystem. The squash4 direct_read() path multiplies attacker-controlled filesystem geometry values without complete overflow checks, so grub_malloc() allocates an undersized buffer before data is copied into it. Exploitation requires access that causes GRUB to read the crafted filesystem; successful corruption executes code in the bootloader and bypasses Secure Boot protections.

The record

CVE
CVE-2025-0678
Published
Mar 3, 2025
Updated
Jun 29, 2026
Vendor
The GnuPG Project
Product
GNU GRUB
Classifications
CWE-787, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 3, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 29, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=2.12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The GnuPG Project · GNU GRUBversion=0 <=2.12

Published CVSS scores

6.4GNU ProjectCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
7.8Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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