CVE-2025-54770
📋 TL;DR
A use-after-free vulnerability in GRUB2's network module allows attackers to cause denial of service by executing the net_set_vlan command after module unloading. This affects systems using GRUB2 with network boot capabilities. Successful exploitation crashes the system during boot, halting availability.
💻 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
Complete system crash during boot process, making the system unbootable and requiring physical intervention to restore.
Likely Case
System instability or crash during network boot operations, disrupting services that rely on network booting.
If Mitigated
Minimal impact if network boot is disabled or proper access controls prevent unauthorized GRUB command execution.
🎯 Exploit Status
Requires ability to execute GRUB commands during boot, typically needing physical access or compromised boot infrastructure.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor-specific updates (Red Hat, Ubuntu, etc.) as patches are released
Vendor Advisory: https://access.redhat.com/security/cve/CVE-2025-54770
Restart Required: Yes
Instructions:
1. Check your distribution's security advisories. 2. Update GRUB2 package via package manager. 3. Reboot system to load patched GRUB.
🔧 Temporary Workarounds
Disable network boot
linuxRemove or disable network boot configuration to prevent loading of vulnerable module
Edit /etc/default/grub and remove netboot references
Update grub config: update-grub or grub2-mkconfig
Secure boot environment
linuxSet GRUB password to prevent unauthorized command execution
grub2-mkpasswd-pbkdf2
Add password to /etc/grub.d/40_custom
update-grub
🧯 If You Can't Patch
- Disable network boot functionality completely
- Implement physical security controls to prevent unauthorized access to boot process
🔍 How to Verify
Check if Vulnerable:
Check GRUB version and if network module is loaded: grep -i net /boot/grub2/grub.cfgCheck Version:
grub2-install --version or rpm -q grub2 or dpkg -l grub2Verify Fix Applied:
Verify GRUB package version matches patched version from vendor advisory📡 Detection & Monitoring
Log Indicators:
- System crashes during boot
- GRUB error messages related to network module
Network Indicators:
- Unexpected network boot attempts
- TFTP/DHCP traffic during system boot
SIEM Query:
source="kernel" AND "GRUB" AND ("crash" OR "panic" OR "network")