CVE-2023-45234 is a high severity buffer overflow, scored 8.3, in the EDK2 network package. A DNS Servers option in a DHCPv6 Advertise message can overflow a buffer. The fix is in edk2-stable202402, so update firmware or disable PXE boot. Disable PXE boot if you cannot update yet.
What's affected
The advisory for the EDK2 network stack (tracked as GHSA-hc6x-cw6p-gj7h) lists NetworkPkg in EDK2 up to and including the 202311 release as affected. The NVD record shows the product as TianoCore EDK2 with no version bounds, so the advisory is the more precise source.
The advisory lists these releases as fixed:
- CVE-2023-45229 through CVE-2023-45235 are fixed in edk2-stable202402.
- CVE-2023-45236 and CVE-2023-45237 are fixed in edk2-stable202405.
EDK2 is the open source UEFI firmware reference code. Many vendors build their own firmware from it, so the version you need to look at is your firmware vendor's release, not the EDK2 tag. Virtual machine firmware such as OVMF is built from the same code.
How to check if you're exposed
You need to know two things: whether your machines run an EDK2 based firmware, and whether network boot is enabled on them.
On a Linux host you can read the firmware vendor and version from the DMI tables:
sudo dmidecode -t bios
For virtual machines that use OVMF, check the packaged firmware build on the hypervisor host:
dpkg -l | grep -i ovmf
rpm -q edk2-ovmf
Compare the result with your vendor's advisory, since vendors backport fixes under their own version numbers. Then look in firmware setup, or in your fleet tooling, for PXE or HTTP boot settings. The advisory states that exploitation needs PXE boot enabled, that it is off by default, and that it is often turned on for servers and some laptops.
What to do now
- List the systems whose firmware is built from EDK2, including virtual machines that use OVMF, and record the firmware version of each.
- Update to firmware that includes EDK2 stable 202402 or later.
- If you cannot update yet, turn off PXE and HTTP boot on machines that do not need network boot, as the advisory suggests.
- Keep firmware update status in the same inventory as your software dependencies, so a future firmware advisory is a query and not a project.
Why it matters
The weakness is a buffer overflow, CWE-119, reached through the DNS Servers option of a DHCPv6 Advertise message. Advertise messages come from DHCPv6 servers, and the booting machine trusts the reply it receives on the local network. The record says a successful attack could affect confidentiality, integrity and availability.
The vector is CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H, an adjacent network attack needing no privileges and no user action. The practical question for defenders is who can place a DHCPv6 server on the segment where machines boot. Network controls such as DHCPv6 guard features on switches reduce that risk, though they do not replace the firmware fix.
This CVE is not on the CISA KEV list, and the advisory does not report exploitation.
Safeguard's free in-browser dependency scan at gold.safeguard.sh/scan reads the manifests and lockfiles of software projects. It will not see firmware or device images, so for this issue the asset inventory and the vendor advisory are your main tools.
Quick check
Which message carries the bad option?
Per the record, the DNS Servers option inside a DHCPv6 Advertise message.
Can network controls help?
They can narrow who is able to send such messages, but the advisory's remedy is patched firmware or disabled PXE boot.
Sources
Last reviewed: 19 October 2026.
