CVE-2025-0677

Code execution via overflowing UFS symlink size

Published Feb 19, 2025 · Updated Jun 29, 2026

Heap-based buffer overflow in GNU GRUB 2.12 and earlier allows local users to execute code via a crafted UFS filesystem. grub_ufs_lookup_symlink allocates a buffer from an unchecked, overflowing inode size and then copies the full symlink data past its end. Exploitation requires privileged placement or use of malicious boot media and can corrupt GRUB's heap, execute pre-OS code, and bypass Secure Boot.

CVSS severity6.4
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in GNU GRUB 2.12 and earlier allows local users to execute code via a crafted UFS filesystem. grub_ufs_lookup_symlink allocates a buffer from an unchecked, overflowing inode size and then copies the full symlink data past its end. Exploitation requires privileged placement or use of malicious boot media and can corrupt GRUB's heap, execute pre-OS code, and bypass Secure Boot.

The record

CVE
CVE-2025-0677
Published
Feb 19, 2025
Updated
Jun 29, 2026
Vendor
The GnuPG Project
Product
GNU GRUB
Classifications
CWE-787, T1542.003
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Feb 19, 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 privilegesadmin

What is affected?

The GnuPG Project · GNU GRUBversion=0 <=2.12
389 Directory Server · Red Hat Enterprise Linux 10Affected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.
389 Directory Server · Red Hat OpenShift Container Platform 4Affected versions are unavailable in this record.

Published CVSS scores

6.4UbuntuCVSS:3.1/AV:L/AC:H/PR:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1542.003Pre-OS Boot: Bootkit

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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