{"identifier":"CVE-2026-97631","cve":{"id":"CVE-2026-97631","description":"EDK2 contains a vulnerability in BIOS where a user may cause “Out-of-bounds\nWrite”, Classic\nBuffer Overflow, and “Incorrect Calculation of Buffer Size” by remote access. Successful exploitation of this vulnerability\ncan lead to arbitrary\ncode execution. It could also impact\nConfidentiality,\nIntegrity,\nand Availability.","published":"2026-10-22T17:17:02.027000+00:00","modified":"2026-10-28T16:17:10.317000+00:00","status":"Deferred","score":9.5,"severity":"CRITICAL","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/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","cvss_version":"4.0","affected":[],"weaknesses":["CWE-120","CWE-131","CWE-787"],"references":[{"url":"https://github.com/tianocore/edk2/security/advisories/GHSA-99cj-7hg9-mp4m","source":"infosec@edk2.groups.io"},{"url":"http://www.openwall.com/lists/oss-security/2026/10/28/4","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://arstechnica.com/security/2026/10/code-execution-flaw-in-uefi-firmware-threatens-most-servers-on-planet-earth/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/microsoft/mu_basecore/pull/1989","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/microsoft/mu_basecore/pull/1990","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://news.ycombinator.com/item?id=50265393","source":"af854a3a-2127-422b-91ae-364da2661108"}],"kev":null,"kev_checked":true,"metrics":{"cvssMetricV40":[{"source":"infosec@edk2.groups.io","type":"Secondary","cvssData":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/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","baseScore":9.5,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"HIGH","subIntegrityImpact":"HIGH","subAvailabilityImpact":"HIGH","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}}]},"configurations":[],"source":"nvd","retrieved_at":"2026-10-28T17:25:37.813439+00:00","exploited":false,"kev_stale":false,"products":[],"priority":{"label":"Critical technical severity","reasons":["CVSS is at least 9.0; exploitation is not established by severity alone."]},"epss":{"probability":0.00432,"percentile":0.37373,"date":"2026-10-27","stale":false},"version_assessment":null},"news":[],"campaigns":[],"domains":[{"domain":"github.com","source_url":"https://github.com/tianocore/edk2/security/advisories/GHSA-99cj-7hg9-mp4m","investigate_url":"https://investigate.aeglixmind.com/#github.com"},{"domain":"www.openwall.com","source_url":"http://www.openwall.com/lists/oss-security/2026/10/28/4","investigate_url":"https://investigate.aeglixmind.com/#www.openwall.com"},{"domain":"arstechnica.com","source_url":"https://arstechnica.com/security/2026/10/code-execution-flaw-in-uefi-firmware-threatens-most-servers-on-planet-earth/","investigate_url":"https://investigate.aeglixmind.com/#arstechnica.com"},{"domain":"news.ycombinator.com","source_url":"https://news.ycombinator.com/item?id=50265393","investigate_url":"https://investigate.aeglixmind.com/#news.ycombinator.com"}],"arsenal_url":"https://arsenal.aeglixmind.com/?cve=CVE-2026-97631","catalog_url":"https://cves.aeglixmind.com/cve/CVE-2026-97631","research_url":"https://investigate.aeglixmind.com/research/cve/CVE-2026-97631","coverage":{"news_candidates_checked":0,"campaign_candidates_checked":0,"bounded":false,"notice":"Exact CVE mentions in stored public excerpts and reviewed campaign content only. A mention is not proof of exploitation, attribution or tool suitability. Missing matches do not establish absence."}}