CVE-2025-54771
📋 TL;DR
A use-after-free vulnerability in GNU GRUB's file-closing process allows attackers to cause bootloader crashes, leading to denial of service. This affects systems using vulnerable GRUB versions during boot operations. While data compromise is possible, the primary impact is system availability.
💻 Affected Systems
- GNU GRUB (Grand Unified Bootloader)
⚠️ 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 fails to boot, requiring physical intervention or recovery media, with potential for arbitrary code execution during boot process.
Likely Case
GRUB crashes during boot, causing system to hang or reboot, resulting in temporary denial of service until manual intervention.
If Mitigated
Limited to boot-time attacks requiring physical access or compromised boot environment, with minimal impact on running systems.
🎯 Exploit Status
Exploitation requires triggering specific file operations during boot; complexity depends on attacker's access to boot environment.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check distribution-specific updates (e.g., grub2-2.06-* updates for Red Hat)
Vendor Advisory: https://access.redhat.com/security/cve/CVE-2025-54771
Restart Required: Yes
Instructions:
1. Check your distribution's security advisories. 2. Update GRUB packages via package manager. 3. Regenerate GRUB configuration. 4. Reboot system to apply changes.
🔧 Temporary Workarounds
Secure Boot Enforcement
linuxEnable Secure Boot to prevent unauthorized boot modifications
Check with: mokutil --sb-state
Enable via UEFI/BIOS settings
Boot Partition Protection
linuxSet immutable flags on boot partition to prevent modifications
chattr +i /boot/grub2/grub.cfg
chattr +i /boot/grub2/*
🧯 If You Can't Patch
- Restrict physical access to systems and secure boot environment
- Implement monitoring for boot partition modifications and failed boot attempts
🔍 How to Verify
Check if Vulnerable:
Check GRUB version: grub2-install --version or rpm -q grub2Check Version:
grub2-install --versionVerify Fix Applied:
Verify updated package: rpm -q grub2 --changelog | grep CVE-2025-54771📡 Detection & Monitoring
Log Indicators:
- Failed boot attempts in system logs
- GRUB error messages in /var/log/messages or journalctl
Network Indicators:
- Not applicable - local boot-time vulnerability
SIEM Query:
source="*messages*" AND "GRUB" AND ("error" OR "fail*")