CVE-2026-54333: UEFI Firmware Parser: Stack out-of-bounds write in tiano decompressor MakeTable
UEFI Firmware Parser parses BIOS, Intel ME, and UEFI firmware structures including volumes, file systems, and files. Prior to 1.14, MakeTable() in uefifirmware/compression/Tiano/Decompress.c does not validate that bit-length values read from a crafted Tiano or EFI compressed firmware bitstream remain within the expected range from 0 through 16. The normal CompressedSection.process() to eficompressor.TianoDecompress() to TianoDecompress() to ReadPTLen() to MakeTable() parsing path can consequently write beyond the stack-allocated Count[17] array and related decode tables. The resulting stack corruption deterministically crashes the parsing process and may permit code execution depending on build and runtime details. This issue is fixed in version 1.14.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
UEFI Firmware Parserto a version that resolves this vulnerability.Fixed in 1.14
Event History
Frequently Asked Questions
Which deployments are exposed to this issue?
Deployments using UEFI Firmware Parser versions prior to 1.14 are affected when they parse crafted Tiano- or EFI-compressed firmware data through the normal compressed-section processing path.
What does an attacker need to exploit the flaw?
An attacker needs to supply a crafted compressed firmware bitstream containing invalid bit-length values. The stated vector requires no privileges or user interaction and has low attack complexity.
What is the practical impact of successful exploitation?
The malformed input causes stack corruption by writing beyond the Count[17] array and related decode tables. This deterministically crashes the parsing process and may allow code execution depending on build and runtime details.
How should this be remediated?
Upgrade UEFI Firmware Parser to version 1.14, which fixes the missing bit-length validation in MakeTable().