{"id":"CVE-2021-33626","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-33626","generatedAt":"2026-10-27T22:32:23.347Z","title":"A vulnerability exists in SMM (System Management Mode) branch that registers a SWSMI handler that does not sufficiently check or validate the allocated buffer pointer(QWORD values for CommBuffer).","description":"A vulnerability exists in SMM (System Management Mode) branch that registers a SWSMI handler that does not sufficiently check or validate the allocated buffer pointer(QWORD values for CommBuffer). This can be used by an attacker to corrupt data in SMRAM memory and even lead to arbitrary code execution.","published":"2021-10-01T03:15:07.000Z","lastModified":"2026-08-11T13:17:20.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.1","score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-829"],"affected":["insyde/insydeh2o","siemens/ruggedcom apr1808 firmware","siemens/simatic field pg m5 firmware","siemens/simatic field pg m6 firmware","siemens/simatic ipc127e firmware","siemens/simatic ipc227g firmware","siemens/simatic ipc277g firmware","siemens/simatic ipc327g firmware","siemens/simatic ipc377g firmware","siemens/simatic ipc427e firmware","siemens/simatic ipc477e firmware","siemens/simatic ipc477e pro firmware","siemens/simatic ipc627e firmware","siemens/simatic ipc647e firmware","siemens/simatic ipc677e firmware","siemens/simatic ipc847e firmware","siemens/simatic itp1000 firmware"],"epss":{"score":0.00308,"percentile":0.23406,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.31%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-306654.pdf","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://security.netapp.com/advisory/ntap-20220216-0006/","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://www.insyde.com/security-pledge","tags":["Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://www.insyde.com/security-pledge/SA-2021001","tags":["Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-306654.pdf","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20220216-0006/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.insyde.com/security-pledge","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.insyde.com/security-pledge/SA-2021001","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.kb.cert.org/vuls/id/796611","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-306654.html","source":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-33626","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}