CVE-2025-0677
📋 TL;DR
This CVE-2025-0677 vulnerability in grub2's UFS module allows heap buffer overflow when processing malicious symlinks. Attackers can exploit this to corrupt heap data and potentially execute arbitrary code, bypassing secure boot protections. Systems using grub2 with UFS filesystem support are affected.
💻 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 compromise via arbitrary code execution, secure boot bypass allowing persistent malware installation, and potential privilege escalation to kernel level.
Likely Case
System instability, data corruption, and potential secure boot bypass in targeted attacks against systems with UFS filesystems.
If Mitigated
Limited impact if secure boot is properly configured and systems don't use UFS filesystems, though heap corruption could still cause crashes.
🎯 Exploit Status
Exploitation requires crafting a malicious UFS filesystem and physical/local access to boot from it. Secure boot bypass adds complexity.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor-specific updates (e.g., Red Hat RHSA-2025:16154, RHSA-2025:6990)
Vendor Advisory: https://access.redhat.com/security/cve/CVE-2025-0677
Restart Required: Yes
Instructions:
1. Update grub2 package via system package manager. 2. Update grub configuration: 'grub2-mkconfig -o /boot/grub2/grub.cfg'. 3. Reboot system.
🔧 Temporary Workarounds
Disable UFS module
linuxRemove UFS filesystem support from grub to prevent exploitation
echo 'GRUB_DISABLE_UFS="true"' >> /etc/default/grub
grub2-mkconfig -o /boot/grub2/grub.cfg
🧯 If You Can't Patch
- Restrict physical access to systems and secure boot media
- Implement secure boot with trusted keys only and disable boot from external media
🔍 How to Verify
Check if Vulnerable:
Check grub2 version: 'rpm -q grub2' (RHEL) or 'dpkg -l | grep grub' (Debian/Ubuntu) and compare against patched versions in vendor advisories.Check Version:
rpm -q grub2 --qf '%{version}-%{release}\n' # RHEL/CentOS/Fedora or dpkg -l | grep '^ii.*grub' # Debian/UbuntuVerify Fix Applied:
Verify grub2 package version matches patched version from vendor advisory and check that UFS module is disabled if using workaround.📡 Detection & Monitoring
Log Indicators:
- Kernel panic during boot
- Grub error messages related to UFS or symlink processing
- Secure boot validation failures
Network Indicators:
- None - local exploitation only
SIEM Query:
source="boot.log" AND ("grub" AND ("UFS" OR "symlink" OR "panic"))