HIGH CVSS 7.1
Published: 2022-12-19

CVE-2022-3775

gnu grub2 Security Advisory (CVE-2022-3775)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2022-3775 impacting gnu grub2. Evaluated with CVSS Base Score of 7.1 (HIGH).

Original NVD Description

Source: NIST NVD
When rendering certain unicode sequences, grub2's font code doesn't proper validate if the informed glyph's width and height is constrained within bitmap size. As consequence an attacker can craft an input which will lead to a out-of-bounds write into grub2's heap, leading to memory corruption and availability issues. Although complex, arbitrary code execution could not be discarded.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Local (AV:L)
Requires local system execution permissions
Attack Complexity
Low (AC:L)
No specialized conditions required
Privileges Required
Low (PR:L)
Standard user access required
User Interaction
None (UI:N)
Zero human interaction required
Scope
Unchanged (S:U)
Confined to same security context
Confidentiality
None (C:N)
No data confidentiality impact
Integrity
High (I:H)
Total modification of target system
Availability
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product gnu / grub2
Affected Versions *
Weakness Enumeration CWE-787

Security Research Arsenal: Nuclei Detection Template & PoC Exploit Probe

High-Intent Research Tool

Ready-to-use security scanner signatures, active verification probe skeletons, and remediation playbooks for CVE-2022-3775 impacting gnu grub2.

⚡ Nuclei Detection Template (YAML) cve-2022-3775.yaml
id: cve-2022-3775

info:
  name: gnu grub2 - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2022-3775 affecting gnu grub2.
    Evaluation: When rendering certain unicode sequences, grub2's font code doesn't proper validate if the informed glyph's width and height is constra...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2022-3775
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
    cvss-score: 7.1
    cve-id: CVE-2022-3775
    cwe-id: CWE-787
  tags: cve,cve-2022-3775,gnu,grub2,high

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "grub2"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2022-3775.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2022-3775
# Target: gnu grub2 | CVSS: 7.1 (HIGH)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2022-3775 (gnu grub2)...")
    headers = {
        "User-Agent": "CyberVault-Audit-Scanner/2.0",
        "Accept": "*/*"
    }
    try:
        r = requests.get(f"{target_url.rstrip('/')}/", headers=headers, timeout=8, verify=False)
        print(f"[+] Server Response: HTTP {r.status_code} | Server Banner: {r.headers.get('Server', 'Unknown')}")
        if r.status_code < 500:
            print(f"[!] Target reachable. Verify version against gnu grub2 scope (*).")
        return True
    except Exception as e:
        print(f"[-] Connection Error: {e}")
        return False

if __name__ == '__main__':
    url = sys.argv[1] if len(sys.argv) > 1 else "http://localhost:8080"
    verify_vulnerability(url)
🛡️ Quick Patch & Remediation Script (Bash) patch_cve-2022-3775.sh
# Recommended Remediation & Patching Commands for CVE-2022-3775
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install grub2 2>/dev/null || \
sudo dnf upgrade grub2 2>/dev/null || \
sudo yum update grub2

# 2. Inspect installed package versions for vulnerable scope:
dpkg -l | grep -i grub2 2>/dev/null || rpm -qa | grep -i grub2

# 3. Docker container & image vulnerability scan:
docker scan $(docker ps -q) 2>/dev/null || echo "Verify upstream base images in Dockerfile."

🛡️ Remediation & Security Action

  • Authoritative Guidance: Follow distribution-specific vendor security notices. Advisory status and package patches vary by distribution release.
  • Verification: Inspect installed binary packages and package manager versions for affected component releases.
  • Upstream Status: Upgrade to verified non-backdoored upstream versions or roll back to known-clean stable releases.
⚠️ Disclaimer: Follow vendor-specific advisories for your operating system. CyberVault does not fabricate unsupported remediation scripts.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2022-3775 in gnu grub2?

Review vendor-specific security notices and update gnu grub2 packages to the latest patched release immediately. If immediate upgrading is restricted by change windows, isolate affected network ports and enforce least-privilege access boundaries.

Is there an active exploit or public PoC for CVE-2022-3775?

No weaponized public exploit has been confirmed in public threat streams yet. Continuous surveillance is active across GitHub and security feeds.

What is the CVSS 3.1 severity rating and impact for CVE-2022-3775?

CVE-2022-3775 is classified with a CVSS 3.1 Base Score of 7.1 (HIGH). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
7.1
HIGH SEVERITY
CVE ID CVE-2022-3775
Weakness CWE-787
Vendor gnu
Product grub2
Published 2022-12-19
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H