CVE-2026-5818

HIGH

MCU Firmware Update Authentication Bypass on Caliptra Core

Title source: cna

Description

Incorrect check of function return value in Caliptra Core Runtime Firmware (ActivateFirmwareCmd::activate_fw modules) allows bypass of Caliptra Core's verification of the MCU FW during a hitless update. This issue affects Core Runtime Firmware: from 2.0.0 through 2.0.1, 2.1.0.

References (1)

Core 1

Core References

https://github.com/chipsalliance/caliptra-sw/security/advisories/GHSA-456r-gcjr-6rxq

Scores

CVSS v4 7.2

EPSS 0.0015

EPSS Percentile 5.1%

CVSS:4.0/AV:A/AC:L/AT:P/PR:H/UI:N/VC:N/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CISA SSVC

Vulnrichment

Exploitation none

Automatable no

Technical Impact partial

Details

CWE

CWE-253

Status published

Products (4)

Caliptra/Core Runtime Firmware 2.0.0 - 2.0.1

Caliptra/Core Runtime Firmware 2.0.2

Caliptra/Core Runtime Firmware 2.1.0

Caliptra/Core Runtime Firmware 2.1.1

Published Jun 24, 2026

Tracked Since Jun 24, 2026