CVE-2025-0624 – This CVE-2025-0624 vulnerability in grub2 allow... (How to Fix)

Q: What is the severity of CVE-2025-0624?

CVE-2025-0624 has a CVSS score of 7.6 (HIGH). This CVE-2025-0624 vulnerability in grub2 allows remote attackers on the same network segment to execute arbitrary code during network boot by exploiting an out-of-bounds write in environment variable handling. This can bypass secure boot protections and compromise system integrity. Systems using grub2 for network boot are affected.

📋 TL;DR

This CVE-2025-0624 vulnerability in grub2 allows remote attackers on the same network segment to execute arbitrary code during network boot by exploiting an out-of-bounds write in environment variable handling. This can bypass secure boot protections and compromise system integrity. Systems using grub2 for network boot are affected.

💻 Affected Systems

Products:

grub2

Versions: All versions before patched releases in Red Hat advisories

Operating Systems: Linux distributions using grub2 for network boot

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems using network boot feature; local boot systems are not vulnerable.

⚠️ 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.

Recommended Actions:

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

Remote code execution leading to full system compromise, secure boot bypass, and persistent malware installation.

🟠

Likely Case

Local network attackers gaining control of boot process to install backdoors or ransomware.

🟢

If Mitigated

Limited to denial of service or failed boot if exploit fails.

🌐 Internet-Facing: LOW - Requires attacker on same network segment during boot process.

🏢 Internal Only: MEDIUM - Internal attackers with network access during boot can exploit.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires attacker on same network segment during boot process and knowledge of network boot configuration.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Check specific Red Hat advisories for version numbers

Vendor Advisory: https://access.redhat.com/errata/RHSA-2025:2521

Restart Required: No

Instructions:

1. Update grub2 package using system package manager. 2. For Red Hat systems: 'yum update grub2' or 'dnf update grub2'. 3. Regenerate grub configuration if needed.

🔧 Temporary Workarounds

Disable network boot

all

Prevent exploitation by disabling network boot functionality

Edit /etc/default/grub and remove network boot options
Run 'grub2-mkconfig -o /boot/grub2/grub.cfg'

Network segmentation

all

Isolate network boot traffic to trusted segments

Configure network switches to restrict bootp/dhcp traffic
Use VLANs to separate boot network

🧯 If You Can't Patch

Implement strict network access controls for boot servers
Use physical security measures to prevent unauthorized network access during boot

🔍 How to Verify

Check if Vulnerable:

Check grub2 version and compare against patched versions in Red Hat advisories

Check Version:

rpm -q grub2  # Red Hat systems

Verify Fix Applied:

Verify grub2 package version matches patched version from vendor advisory

📡 Detection & Monitoring

Log Indicators:

Unusual network boot attempts
Failed boot processes with memory errors

Network Indicators:

Suspicious DHCP/TFTP traffic during boot cycles
Unexpected network boot requests

SIEM Query:

source="boot.log" AND "grub" AND ("error" OR "fail")

📊 Metadata

CVE ID: CVE-2025-0624

CVSS v3 Score: 7.6 (HIGH)

CVSS Vector: CVSS:3.1/AV:A/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

CWE: CWE-787

EPSS Score: 2.49% exploit probability (85th percentile)

Published: February 19, 2025

Last Updated: May 21, 2025

🔗 References

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