CVE-2023-45235 is a high severity buffer overflow, scored 8.3, in the EDK2 network package. Handling the Server ID option of a DHCPv6 proxy Advertise message can overflow a buffer. The fix is in edk2-stable202402, so update firmware or disable PXE boot.
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, in how the DHCPv6 client handles the Server ID option when the message is a proxy Advertise. It is a close relative of CVE-2023-45230, which covers a long server ID in the ordinary DHCPv6 path.
The vector is CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H. As with the others in this group, the attacker must be adjacent to the booting machine. The record's description says confidentiality, integrity and availability could all be affected.
No exploitation is reported in the advisory, and the CVE is not on the CISA KEV list. For fleets, the useful lesson is that one patch release covered seven CVEs in the first group, so tracking by release is simpler than tracking by CVE.
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
Is this the same as CVE-2023-45230?
No. Same class and a similar option, but this one is in the proxy Advertise path.
What is the fixed release?
The GitHub advisory lists edk2-stable202402 for this CVE.
Sources
Last reviewed: 19 October 2026.
