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VulnerabilityPublished

CVE-2026-5818: Caliptra Core Runtime Firmware · Incorrect Check of Function Return Value

Affects Caliptra Core Runtime FirmwareSource CVE Database V5

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Not known to be exploited · CVSS 7.2 High.

Data as of 5 Nov 2026, 00:01 UTC

CVSS 4.0 base score
7.2High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 15% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
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

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 23 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.

What to do

Affected software

ProductAffectedFixed in
CaliptraCore Runtime FirmwareAffected
  • >=2.0.0 <=2.0.1
  • =2.1.0
Fixed in–
GitHubCore Runtime Firmwarepkg:github/Core Runtime FirmwareOther threatsAffected
  • >=2.0.0 <=2.0.1
  • =2.1.0
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Until a fix is available, restrict access to the update mechanism to trusted administrators and monitor for unusual firmware update activity. Follow vendor communications for updates on patches or official mitigations.

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

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