Pre-boot RCE in EDK II PXE driver

Summary

EDK2 contains a vulnerability in BIOS where a user may cause “Out-of-bounds Write”, Classic Buffer Overflow, and “Incorrect Calculation of Buffer Size” by remote access. Successful exploitation of this vulnerability can lead to arbitrary code execution. It could also impact Confidentiality, Integrity, and Availability.

Remediation

1. Inventory every TianoCore EDK2 deployment, including staging.
2. No fixed version appears in the public sources yet. Check the references below and the vendor directly.

References

• Referencehttps://github.com/tianocore/edk2/security/advisories/GHSA-99cj-7hg9-mp4m
• Referencehttps://arstechnica.com/security/2026/10/code-execution-flaw-in-uefi-firmware-threatens-most-servers-on-planet-earth/
• Referencehttps://github.com/microsoft/mu_basecore/pull/1989
• Referencehttps://github.com/microsoft/mu_basecore/pull/1990
• Referencehttps://news.ycombinator.com/item?id=50265393