CVE-2023-45233 is a high severity infinite loop, scored 7.5, in the EDK2 network package. Parsing a PadN option in an IPv6 Destination Options header can hang the firmware. 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
This is a sibling of CVE-2023-45232. Both are the same weakness class, CWE-835, in the same IPv6 header, but through a different option. Here the trigger is a PadN option, which in IPv6 is padding. The record's description says the result is a loss of availability.
The vector is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Two separate CVEs in one parser is a useful hint: when option parsing code has one loop bug, reviewers should read every option handler, not only the one reported.
Neither the record nor the advisory reports exploitation, and the CVE is not on the CISA KEV list. The advisory states that PXE boot must be enabled for 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
How is this different from CVE-2023-45232?
Same weakness class and same header, but the PadN option triggers this one and unknown options trigger the other.
Is there a workaround?
The advisory says disabling PXE boot reduces exposure. The real fix is patched firmware.
Sources
Last reviewed: 19 October 2026.
