MCU Firmware Update Authentication Bypass on Caliptra Core
Priority LOW 31CWE-253Published · Updated
Key facts
- Attack vector
- Adjacent network
- Privileges required
- High
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- —
- Confidentiality · integrity · availability
- None · High · High
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA.
Summary
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00245 15th percentileScored 2026-11-07
Fix Fixed Core Runtime Firmware (Caliptra): 2.0.2, 2.1.1
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA Core Runtime Firmware (Caliptra) Fixed in 2.0.2, 2.1.1
Timeline
- 2026-10-02 Threatist record created from CVE-2026-5818
References
More Caliptra vulnerabilities
- TI-2026-06435 Unverified AXI Address in Subsystem Mode Commands Enables Denial of Service CVSS 4.0MEDIUM 6.8
- TI-2026-10213 Caliptra Update-Reset Secure-Boot Bypass via Attacker-Chosen AXI Staging Address (TOCTOU) CVSS 4.0MEDIUM 5.6
- TI-2026-05666 AES-256-GCM Authentication Tag Does Not Cover First Ciphertext Blocks When AAD Is Empty CVSS 4.0MEDIUM 5.1
- TI-2026-10214 Production Debug-Unlock Token Verification Missing Device Binding CVSS 4.0LOW 1.8
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences