CVE-2026-5818

MCU Firmware Update Authentication Bypass on Caliptra Core

State: Published
Severity: 7.2 High
Published: Jun 23, 2026
Updated: Jun 24, 2026
Reserved: Apr 8, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	7.2 High	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	Caliptra

Weaknesses

CWE-253 Incorrect check of function return value

Affected Products

Product	Versions
Core Runtime FirmwareCaliptra	2.0.0 through 2.0.1Affected 2.1.0Affected 2.0.2Not affected 2.1.1Not affected

References

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

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