CVE-2023-45234 – A buffer overflow vulnerability in EDK2's Netwo... (How to Fix)

Q: What is the severity of CVE-2023-45234?

CVE-2023-45234 has a CVSS score of 8.3 (HIGH). A buffer overflow vulnerability in EDK2's Network Package allows attackers to execute arbitrary code by sending malicious DHCPv6 Advertise messages. This affects systems using EDK2-based firmware with IPv6 networking enabled, potentially compromising UEFI firmware integrity. The vulnerability can lead to complete system compromise before the operating system loads.

📋 TL;DR

A buffer overflow vulnerability in EDK2's Network Package allows attackers to execute arbitrary code by sending malicious DHCPv6 Advertise messages. This affects systems using EDK2-based firmware with IPv6 networking enabled, potentially compromising UEFI firmware integrity. The vulnerability can lead to complete system compromise before the operating system loads.

💻 Affected Systems

Products:

EDK2 (UEFI Development Kit)
Systems using EDK2-based firmware
Various UEFI implementations derived from EDK2

Versions: EDK2 versions prior to commit 6a506c7 (2024-01-16)

Operating Systems: All operating systems running on affected UEFI firmware

Default Config Vulnerable: ⚠️ Yes

Notes: Requires IPv6 networking enabled and DHCPv6 configuration. Many modern systems have IPv6 enabled by default. Virtual machines and cloud instances may also be affected.

📦 What is this software?

Edk2 by Tianocore

View all CVEs affecting Edk2 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete system compromise with persistent firmware-level malware that survives OS reinstallation and disk replacement, enabling long-term espionage or destruction of hardware.

🟠

Likely Case

Remote code execution at firmware level leading to OS compromise, data theft, or system instability requiring physical hardware remediation.

🟢

If Mitigated

Limited impact if IPv6 is disabled or network segmentation prevents DHCPv6 traffic from untrusted sources.

🌐 Internet-Facing: MEDIUM - Requires attacker to be on the same network segment and send DHCPv6 traffic, but cloud/VM environments could be vulnerable if network isolation fails.

🏢 Internal Only: HIGH - Internal attackers or compromised devices on the same network can exploit this to gain persistent access to multiple systems.

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: LIKELY

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Proof-of-concept code is publicly available as part of the PixieFail research. Exploitation requires network access but no authentication. The vulnerability is in pre-boot firmware, making detection difficult.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: EDK2 commit 6a506c7 and later

Vendor Advisory: https://github.com/tianocore/edk2/security/advisories/GHSA-hc6x-cw6p-gj7h

Restart Required: Yes

Instructions:

1. Update EDK2 source to commit 6a506c7 or later. 2. Rebuild firmware with patched EDK2. 3. Flash updated firmware to affected systems. 4. Contact hardware vendors for firmware updates if using commercial products.

🔧 Temporary Workarounds

Disable IPv6 in UEFI

all

Prevent exploitation by disabling IPv6 networking at firmware level

Access UEFI/BIOS settings during boot
Navigate to Network/Advanced settings
Disable IPv6 support

Network Segmentation

all

Isolate systems from untrusted DHCPv6 traffic using VLANs or firewalls

Configure network switches to restrict DHCPv6 traffic
Implement firewall rules to block external DHCPv6 Advertise messages
Use RA Guard on network equipment

🧯 If You Can't Patch

Implement strict network segmentation to prevent untrusted devices from sending DHCPv6 messages to vulnerable systems
Deploy network monitoring to detect anomalous DHCPv6 traffic patterns and potential exploitation attempts

🔍 How to Verify

Check if Vulnerable:

Check EDK2 version in firmware settings or consult hardware vendor advisories. Systems built with EDK2 prior to 2024-01-16 are likely vulnerable.

Check Version:

dmidecode -t bios (Linux) or systeminfo (Windows) to check firmware date/version, then consult vendor documentation

Verify Fix Applied:

Verify firmware version includes EDK2 commit 6a506c7 or later. Test with updated PixieFail PoC tools to confirm protection.

📡 Detection & Monitoring

Log Indicators:

Unusual DHCPv6 traffic patterns
Firmware update failures
System instability during boot process

Network Indicators:

Malformed DHCPv6 Advertise packets with oversized DNS Servers option
Unexpected network traffic during pre-boot phase

SIEM Query:

source="dhcp" AND (opcode=5 OR message_type="Advertise") AND option=23 AND length>normal

📊 Metadata

CVE ID: CVE-2023-45234

CVSS v3 Score: 8.3 (HIGH)

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

CWE: CWE-119

Published: January 16, 2024

Last Updated: November 4, 2025

🔗 References

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🔗 Related Vulnerabilities

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