CVE-2025-61661 Grub2: grub2: out-of-bounds write via malicious usb device
A local attacker can cause a denial of service or data corruption in GRUB by connecting a malicious USB device during boot.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-61661?
CVE-2025-61661 is a medium-severity memory corruption vulnerability in GNU Red Hat Enterprise Linux 10, published on 18 Nov 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Weakness: CWE-131
Which versions are affected by CVE-2025-61661?
How do I fix CVE-2025-61661?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2025-61661 being exploited?
There is no known exploitation of CVE-2025-61661 in the wild and no public exploit code.
Sources
Also known as AZL-70526, AZL-70580, DEBIAN-CVE-2025-61661, GHSA-cjch-253g-8hp2, UBUNTU-CVE-2025-61661.