Skip to main content
CRITICAL

CVE-2026-54334

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, ReadCLen() in uefi_firmware/compression/Tiano/Decompress.c reads Number from GetBits(Sd, CBIT) with CBIT = 9 and can obtain 511 entries for the 510-element Sd->mCLen heap array because its loop does not enforce Index < NC. The CharC == 2 run-length path can additionally request up to 531 zero writes through Sd->mCLen[Index++] = 0. The normal CompressedSection.proces

Technical details

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

Frequently asked questions

What is CVE-2026-54334?

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 GetBits(Sd, CBIT) with CBIT = 9 and can obtain 511 entries for the 510-element Sd->mCLen heap array because its loop does not enforce Index < NC. The CharC == 2 run-length path can additionally request up to 531 zero writes through Sd->mCLen[Index++] = 0. The normal CompressedSection.proces

Is CVE-2026-54334 actively exploited?

Active exploitation of CVE-2026-54334 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-2026-54334?

CVE-2026-54334 has a CVSS v3 base score of 9.8 (CRITICAL severity).

Is CVE-2026-54334 affecting your environment?

Use isMalicious to check if any of your IPs or domains are associated with this vulnerability's IOCs.

Check an IPSearch CVEsSIEM & TIP integrations

No credit card required · 500 free checks/month · Free API key

Other 2026 vulnerabilities worth triaging

Ranked by exploit probability (EPSS).

Back to CVE Database