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Critical · 9.8 CVE-2026-54333 EUVD-2026-78064GHSA-2689-5p89-6j3jPYSEC-2026-3393

UEFI Firmware Parser: Stack out-of-bounds write in tiano decompressor MakeTable

Published Sep 14, 2026 · Updated Sep 15, 2026 · Assigned by GitHub_M

Description

UEFI Firmware Parser parses BIOS, Intel ME, and UEFI firmware structures including volumes, file systems, and files. Prior to 1.14, MakeTable() in uefi_firmware/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 efi_compressor.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 products

VendorProductAffectedFixed
theopolis uefi-firmware-parser < 1.14 —

Affected packages

EcosystemPackageAffectedFixedRecord
PyPI uefi-firmware <= 1.12 — GHSA-2689-5p89-6j3j

References