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CRITICAL

CVE-2026-54333

CVSS v3

9.8

CRITICAL

EPSS Score

0.8 %

exploit probability, as of 2026-09-28

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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 consequen

Technical details

Published
2026-09-14
Last Modified
2026-09-15

Frequently asked questions

What is CVE-2026-54333?

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 consequen

Is CVE-2026-54333 actively exploited?

Active exploitation of CVE-2026-54333 has not been confirmed. Its EPSS score was 0.8% on 2026-09-28, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-54333?

CVE-2026-54333 has a CVSS v3 base score of 9.8 (CRITICAL severity).

Is CVE-2026-54333 affecting your environment?

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