CVE-2026-54334

CVE-2026-54334 is a heap out-of-bounds write in the uefi-firmware Python package's native Tiano/EFI decompressor. The flaw is in ReadCLen() within uefi_firmware/compression/Tiano/Decompress.c: it reads a 9-bit value (up to 511) and writes into the 510-element Sd->mCLen heap array without bound...

PYSEC-2026-3394 UEFI Firmware Parser has a heap out-of-bounds write in tiano decompressor ReadCLen

uefi-firmware contains a heap out-of-bounds write vulnerability in the native tiano/EFI decompressor. in uefifirmware/compression/Tiano/Decompress.c, ReadCLen reads Number = GetBitsSd, CBIT with CBIT = 9, so Number can be as large as 511, while the destination array Sd-mCLen has NC = 510 elements...

Out-of-bounds Write

Overview Affected versions of this package are vulnerable to Out-of-bounds Write in the ReadCLen function of the Tiano decompressor. An attacker can cause a crash by supplying specially crafted compressed firmware data that triggers a heap out-of-bounds write during decompression. Remediation...

UEFI Firmware Parser has a heap out-of-bounds write in tiano decompressor ReadCLen

uefi-firmware contains a heap out-of-bounds write vulnerability in the native tiano/EFI decompressor. in uefifirmware/compression/Tiano/Decompress.c, ReadCLen reads Number = GetBitsSd, CBIT with CBIT = 9, so Number can be as large as 511, while the destination array Sd-mCLen has NC = 510 elements...

PT-2026-56684

UEFI Firmware Parser parses BIOS, Intel ME, and UEFI firmware structures including volumes, file systems, and files. Prior to 1.14, ReadCLen in uefi firmware/compression/Tiano/Decompress.c reads Number from GetBitsSd, CBIT with CBIT = 9 and can obtain 511 entries for the 510-element Sd-mCLen heap...