Vulnerability · Published Jun 23, 2026 · Assigned by Caliptra
CVE-2026-5818MCU Firmware Update Authentication Bypass on Caliptra Core
High 7.2
In plain English
A high-severity security flaw in Core Runtime Firmware from Caliptra. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities).
Severity (CVSS 4.0)7.2High
Exploit odds (30 days)0.2%top 84.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Caliptra | Core Runtime Firmware | 2.0.0 – through 2.0.12.1.0 |
Weakness: CWE-253 · Vector: 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