Vulnerability in GNU Grub2
CVE-2025-61661
A vulnerability has been identified in the GRUB (Grand Unified Bootloader) component. This flaw occurs because the bootloader mishandles string conversion when reading information from a USB device, allowing an attacker to exploit inconsistent length values. A local attacker can connect a maliciously configured USB device during the boot sequence to trigger this issue. A successful exploitation may lead GRUB to crash, leading to a Denial of Service. Data corruption may be also possible, although given the complexity of the exploit the impact is most likely limited.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H.
EPSS exploit prediction
EPSS: 0.002 (8.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 8th percentile — 8.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
Weakness classification (CWE)
References
- access.redhat.com/security/cve/CVE-2025-61661 (vdb-entry)
- bugzilla.redhat.com/show_bug.cgi (issue-tracking)
- af854a3a-2127-422b-91ae-364da2661108
Frequently asked questions
- What is CVE-2025-61661?
- CVE-2025-61661 is a medium-severity vulnerability in GNU Grub2, classified under Incorrect Calculation of Buffer Size. CVSS score: 4.8/10. Published 2025-11-18.
- How severe is CVE-2025-61661?
- Medium severity. CVSS v3 base score is 4.8 out of 10.