CVE-2025-0685: Out-of-bounds Write
A flaw was found in grub2. When reading data from a jfs filesystem, grub's jfs filesystem module uses user-controlled parameters from the filesystem geometry to determine the internal buffer size, however, it improperly checks for integer overflows. A maliciouly crafted filesystem may lead some of those buffer size calculations to overflow, causing it to perform a grub_malloc() operation with a smaller size than expected. As a result, the grub_jfs_lookup_symlink() function will write past the internal buffer length during grub_jfs_read_file(). This issue can be leveraged to corrupt grub's internal critical data and may result in arbitrary code execution, by-passing secure boot protections.
AI Analysis
Technical Summary
The vulnerability in grub2's jfs filesystem module arises from improper handling of integer overflows when calculating buffer sizes based on user-controlled filesystem geometry parameters. This can cause grub_malloc() to allocate a smaller buffer than needed, leading the grub_jfs_lookup_symlink() function to write beyond the allocated buffer during grub_jfs_read_file(). Exploitation of this flaw may corrupt critical internal data structures and enable arbitrary code execution, potentially bypassing secure boot mechanisms. The issue affects grub2 version 0 as stated, with no further version details or patches explicitly provided in the available data.
Potential Impact
Successful exploitation can result in corruption of grub's internal critical data and arbitrary code execution, which may bypass secure boot protections. This compromises system integrity at a low-level boot stage, potentially allowing attackers to control the boot process or execute unauthorized code.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory at https://access.redhat.com/security/cve/CVE-2025-0685 for current remediation guidance. No explicit fix or workaround is stated in the provided advisory content. Users should monitor the vendor advisory for updates and apply official patches once available.
CVE-2025-0685: Out-of-bounds Write
Description
A flaw was found in grub2. When reading data from a jfs filesystem, grub's jfs filesystem module uses user-controlled parameters from the filesystem geometry to determine the internal buffer size, however, it improperly checks for integer overflows. A maliciouly crafted filesystem may lead some of those buffer size calculations to overflow, causing it to perform a grub_malloc() operation with a smaller size than expected. As a result, the grub_jfs_lookup_symlink() function will write past the internal buffer length during grub_jfs_read_file(). This issue can be leveraged to corrupt grub's internal critical data and may result in arbitrary code execution, by-passing secure boot protections.
CVSS v3.1
Score 6.4medium
Affected software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in grub2's jfs filesystem module arises from improper handling of integer overflows when calculating buffer sizes based on user-controlled filesystem geometry parameters. This can cause grub_malloc() to allocate a smaller buffer than needed, leading the grub_jfs_lookup_symlink() function to write beyond the allocated buffer during grub_jfs_read_file(). Exploitation of this flaw may corrupt critical internal data structures and enable arbitrary code execution, potentially bypassing secure boot mechanisms. The issue affects grub2 version 0 as stated, with no further version details or patches explicitly provided in the available data.
Potential Impact
Successful exploitation can result in corruption of grub's internal critical data and arbitrary code execution, which may bypass secure boot protections. This compromises system integrity at a low-level boot stage, potentially allowing attackers to control the boot process or execute unauthorized code.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory at https://access.redhat.com/security/cve/CVE-2025-0685 for current remediation guidance. No explicit fix or workaround is stated in the provided advisory content. Users should monitor the vendor advisory for updates and apply official patches once available.
Technical Details
- Data Version
- 5.1
- Assigner Short Name
- redhat
- Date Reserved
- 2025-01-23T19:09:21.691Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/security/cve/CVE-2025-0685","vendor":"Red Hat"}]
Threat ID: 6868be146f40f0eb72a6ac84
Added to database: 07/05/2025, 05:54:28 UTC
Last enriched: 07/02/2026, 22:14:42 UTC
Last updated: 09/10/2026, 19:36:49 UTC
Views: 209
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