CVE-2025-0686
CVE-2025-0686 is a medium-severity vulnerability in Gnu Grub2 with a CVSS 3.x base score of 6.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.
Key facts
- Severity: Medium (CVSS 3.x base score 6.4)
- EPSS exploit prediction: 0% (17th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2025-5576
- Weakness: CWE-787
- Affected product: Gnu Grub2
- Published:
- Last modified:
Description
A flaw was found in grub2. When performing a symlink lookup from a romfs filesystem, grub's romfs filesystem module uses user-controlled parameters from the filesystem geometry to determine the internal buffer size, however, it improperly checks for integer overflows. A maliciously 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_romfs_read_symlink() may cause out-of-bounds writes when the calling grub_disk_read() function. This issue may be leveraged to corrupt grub's internal critical data and can result in arbitrary code execution by-passing secure boot protections.
Frequently asked questions
- What is CVE-2025-0686?
- A flaw was found in grub2. When performing a symlink lookup from a romfs filesystem, grub's romfs filesystem module uses user-controlled parameters from the filesystem geometry to determine the internal buffer size, however, it improperly checks for integer overflows. A maliciously 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_romfs_read_symlink() may cause out-of-bounds writes when the calling grub_disk_read() function. This issue may be leveraged to corrupt grub's internal critical data and can result in arbitrary code execution by-passing secure boot protections.
- How severe is CVE-2025-0686?
- CVE-2025-0686 has a CVSS 3.x base score of 6.4, rated medium severity. It is exploitable over local access with high attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2025-0686 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2025-0686?
- CVE-2025-0686 affects Gnu Grub2. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2025-0686?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2025-0686 have an EU (EUVD) identifier?
- Yes. CVE-2025-0686 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-5576.
- When was CVE-2025-0686 published?
- CVE-2025-0686 was published on 2025-03-03 and last updated on 2026-06-30.
References
- https://access.redhat.com/security/cve/CVE-2025-0686
- https://bugzilla.redhat.com/show_bug.cgi?id=2346121
- https://lists.gnu.org/archive/html/grub-devel/2025-02/msg00024.html
Affected products (1)
- cpe:2.3:a:gnu:grub2:*:*:*:*:*:*:*:*
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