Code execution via undersized JFS symlink buffer
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 JFS filesystem. The JFS module trusts filesystem geometry in size calculations, allowing integer overflow to make grub_malloc() allocate too little before grub_jfs_read_file() fills the buffer. Exploitation requires high local privileges and boot-time access to a malicious JFS volume; successful corruption can bypass Secure Boot protections.
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 JFS filesystem. The JFS module trusts filesystem geometry in size calculations, allowing integer overflow to make grub_malloc() allocate too little before grub_jfs_read_file() fills the buffer. Exploitation requires high local privileges and boot-time access to a malicious JFS volume; successful corruption can bypass Secure Boot protections.
The record
- CVE
- CVE-2025-0685
- Published
- Mar 3, 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
- Mar 3, 2025CVE publishedPublication date reported by the CVE source.
- 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?
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- Affected versionversion=0 <=2.12
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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