{"id":"CVE-2026-5818","state":"PUBLISHED","title":"MCU Firmware Update Authentication Bypass on Caliptra Core","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.\n\nThis issue affects Core Runtime Firmware: from 2.0.0 through 2.0.1, 2.1.0.","publishedAt":"2026-06-23T23:50:06.556Z","updatedAt":"2026-06-24T13:04:40.166Z","severity":{"score":7.2,"label":"High","version":"4.0","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","source":"Caliptra"},"assigner":"Caliptra","products":["Caliptra Core Runtime Firmware"],"affected":[{"vendor":"Caliptra","product":"Core Runtime Firmware","packageName":"Core Runtime Firmware","defaultStatus":"unaffected","versions":[{"version":"2.0.0","status":"affected","lessThanOrEqual":"2.0.1","versionType":"semver"},{"version":"2.1.0","status":"affected","versionType":"semver"},{"version":"2.0.2","status":"unaffected","versionType":"semver"},{"version":"2.1.1","status":"unaffected","versionType":"semver"}],"collectionURL":"https://github.com/chipsalliance/caliptra-sw","modules":["ActivateFirmwareCmd::activate_fw"]}],"references":["https://github.com/chipsalliance/caliptra-sw/security/advisories/GHSA-456r-gcjr-6rxq"],"weaknesses":["CWE-253"],"ingestedAt":"2026-10-29T20:12:32.778Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/5xxx/CVE-2026-5818.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-5818","state":"PUBLISHED","datePublished":"2026-06-23T23:50:06.556Z","dateUpdated":"2026-06-24T13:04:40.166Z","assignerShortName":"Caliptra","assignerOrgId":"b01ddd03-5ef6-483b-b2c5-acba77f1a554","dateReserved":"2026-04-08T15:45:10.928Z"},"containers":{"cna":{"title":"MCU Firmware Update Authentication Bypass on Caliptra Core","descriptions":[{"lang":"en","value":"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.\n\nThis issue affects Core Runtime Firmware: from 2.0.0 through 2.0.1, 2.1.0."}],"affected":[{"vendor":"Caliptra","product":"Core Runtime Firmware","packageName":"Core Runtime Firmware","defaultStatus":"unaffected","versions":[{"version":"2.0.0","status":"affected","lessThanOrEqual":"2.0.1","versionType":"semver"},{"version":"2.1.0","status":"affected","versionType":"semver"},{"version":"2.0.2","status":"unaffected","versionType":"semver"},{"version":"2.1.1","status":"unaffected","versionType":"semver"}],"collectionURL":"https://github.com/chipsalliance/caliptra-sw","modules":["ActivateFirmwareCmd::activate_fw"]}],"references":[{"url":"https://github.com/chipsalliance/caliptra-sw/security/advisories/GHSA-456r-gcjr-6rxq"}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"ADJACENT","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"HIGH","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","subConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","subIntegrityImpact":"HIGH","vulnAvailabilityImpact":"HIGH","subAvailabilityImpact":"HIGH","exploitMaturity":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"HIGH","baseScore":7.2,"vectorString":"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"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-253","lang":"en","description":"CWE-253 Incorrect check of function return value","type":"CWE"}]}],"providerMetadata":{"shortName":"Caliptra","orgId":"b01ddd03-5ef6-483b-b2c5-acba77f1a554","dateUpdated":"2026-06-23T23:50:06.556Z"},"datePublic":"2026-06-23T19:00:00.000Z","impacts":[{"capecId":"CAPEC-115","descriptions":[{"lang":"en","value":"CAPEC-115 Authentication Bypass"}]}],"tags":["x_open-source"],"credits":[{"lang":"en","value":"NVIDIA Offensive Security Research (OSR) team","type":"finder"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 1.0.1"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-24T13:04:30.529915Z","id":"CVE-2026-5818","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-06-24T13:04:40.166Z"}}]}}}