Is CVE-2026-5818 in the CISA KEV catalog?

No. CVE-2026-5818 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-5818?

CVE-2026-5818 has a CVSS v4 base score of 7.2 (HIGH).

What is the EPSS score for CVE-2026-5818?

CVE-2026-5818 has an EPSS score of 0.15% (5th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix or mitigate CVE-2026-5818?

No published fix for CVE-2026-5818 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

CVE & CISA-KEV Catalog

CVE-2026-5818

HIGH

7.2

CVSS v4

NVD

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.

CWE-253

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

CVSS v4 Vector

Exploitability

Attack VectorAdjacent

Attack ComplexityLow

Privileges RequiredHigh

User InteractionNone

Impact

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

Exploit Intelligence

0.15%probability of exploitation in 30 days

5thpercentile

Low risk: more likely to be exploited than 5% of all known CVEs.

References

Other references1

github.com

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-25.