CVE-2025-61664
📋 TL;DR
A memory use-after-free vulnerability in GRUB2's normal module allows attackers to trigger system crashes or potentially compromise data confidentiality and integrity by invoking the normal_exit command after module unloading. This affects systems using GRUB2 bootloader with the vulnerable module loaded. The impact requires local access to the bootloader interface.
💻 Affected Systems
- GRUB2
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
System crash during boot process leading to denial of service, or potential memory corruption enabling arbitrary code execution in bootloader context with elevated privileges.
Likely Case
System crash or boot failure requiring physical intervention or recovery media to restore system functionality.
If Mitigated
Minimal impact if proper access controls prevent unauthorized bootloader access and systems are regularly backed up.
🎯 Exploit Status
Exploitation requires specific timing and conditions during bootloader operation with module unloading sequence.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor-specific updates (Red Hat, Ubuntu, etc.) for patched GRUB2 versions
Vendor Advisory: https://access.redhat.com/security/cve/CVE-2025-61664
Restart Required: Yes
Instructions:
1. Check your distribution's security advisories. 2. Update GRUB2 package via package manager (e.g., 'yum update grub2' for RHEL, 'apt update && apt upgrade grub2' for Debian/Ubuntu). 3. Regenerate GRUB configuration if required. 4. Reboot system to apply changes.
🔧 Temporary Workarounds
Secure Boot Configuration
linuxEnable Secure Boot to prevent unauthorized bootloader modifications and module loading
Check with 'mokutil --sb-state'
Configure via UEFI/BIOS settings
Bootloader Password Protection
linuxSet GRUB2 password to prevent unauthorized access to bootloader interface
Generate password hash: 'grub2-mkpasswd-pbkdf2'
Add to /etc/grub.d/40_custom and regenerate config
🧯 If You Can't Patch
- Implement strict physical access controls to prevent unauthorized bootloader access
- Maintain regular system backups and disaster recovery procedures for quick restoration if system becomes unbootable
🔍 How to Verify
Check if Vulnerable:
Check GRUB2 version and compare against vendor patched versions: 'grub2-install --version' or 'rpm -q grub2' / 'dpkg -l | grep grub'Check Version:
grub2-install --versionVerify Fix Applied:
Verify updated GRUB2 package version matches vendor's patched version and system boots normally📡 Detection & Monitoring
Log Indicators:
- System boot failures
- GRUB error messages in boot logs
- Kernel panic during boot process
Network Indicators:
- Not applicable - local exploitation only
SIEM Query:
Not applicable for network detection; monitor system boot logs and authentication events for physical/local access attempts