{"id":"CVE-2021-33626","aliases":["EUVD-2021-20303","GHSA-9g63-gv45-4242"],"status":"published","title":"In the kernel in Insyde InsydeH2O 5.x, certain SMM drivers did not correctly validate the...","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.","severity":{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-11","score":0.00308,"percentile":0.23912,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-829"],"published":"2021-10-01T02:21:29Z","modified":"2026-08-11T15:31:31Z","products":[{"vendor":"insyde","product":"insydeh2o"},{"vendor":"siemens","product":"ruggedcom ape1808 - bios"},{"vendor":"siemens","product":"ruggedcom_apr1808_firmware"},{"vendor":"siemens","product":"simatic field pg m5"},{"vendor":"siemens","product":"simatic field pg m6"},{"vendor":"siemens","product":"simatic ipc127e"},{"vendor":"siemens","product":"simatic ipc227g"},{"vendor":"siemens","product":"simatic ipc277g"},{"vendor":"siemens","product":"simatic ipc327g"},{"vendor":"siemens","product":"simatic ipc377g"},{"vendor":"siemens","product":"simatic ipc427e"},{"vendor":"siemens","product":"simatic ipc477e"},{"vendor":"siemens","product":"simatic ipc477e pro"},{"vendor":"siemens","product":"simatic ipc627e"},{"vendor":"siemens","product":"simatic ipc647e"},{"vendor":"siemens","product":"simatic ipc677e"},{"vendor":"siemens","product":"simatic ipc847e"},{"vendor":"siemens","product":"simatic itp1000"},{"vendor":"siemens","product":"simatic_field_pg_m5_firmware"},{"vendor":"siemens","product":"simatic_field_pg_m6_firmware"},{"vendor":"siemens","product":"simatic_ipc127e_firmware"},{"vendor":"siemens","product":"simatic_ipc227g_firmware"},{"vendor":"siemens","product":"simatic_ipc277g_firmware"},{"vendor":"siemens","product":"simatic_ipc327g_firmware"},{"vendor":"siemens","product":"simatic_ipc377g_firmware"},{"vendor":"siemens","product":"simatic_ipc427e_firmware"},{"vendor":"siemens","product":"simatic_ipc477e_firmware"},{"vendor":"siemens","product":"simatic_ipc477e_pro_firmware"},{"vendor":"siemens","product":"simatic_ipc627e_firmware"},{"vendor":"siemens","product":"simatic_ipc647e_firmware"},{"vendor":"siemens","product":"simatic_ipc677e_firmware"},{"vendor":"siemens","product":"simatic_ipc847e_firmware"},{"vendor":"siemens","product":"simatic_itp1000_firmware"},{"vendor":"siemens","product":"simatic ipc277g pro"},{"vendor":"siemens","product":"siplus ipc427e"}],"references":[{"url":"https://www.insyde.com/security-pledge","tags":["x_refsource_MISC","x_transferred","Vendor Advisory"]},{"url":"https://www.insyde.com/security-pledge/SA-2021001","tags":["x_refsource_MISC","x_transferred","Vendor Advisory"]},{"url":"https://security.netapp.com/advisory/ntap-20220216-0006/","tags":["x_refsource_CONFIRM","x_transferred","Third Party Advisory"]},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-306654.pdf","tags":["x_refsource_CONFIRM","x_transferred","Third Party Advisory"]},{"url":"https://www.kb.cert.org/vuls/id/796611"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-306654.html"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-33626"},{"url":"https://security.netapp.com/advisory/ntap-20220216-0006"},{"url":"https://github.com/advisories/GHSA-9g63-gv45-4242"}],"sources":{"cve":[{"id":"CVE-2021-33626","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.","status":"published","published":"2021-10-01T02:21:29Z","modified":"2026-08-11T12:22:05.856Z","updated_at":"2026-11-02T14:33:10.204494Z"}],"euvd":[{"id":"EUVD-2021-20303","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.","status":"published","published":"2021-10-01T02:21:29Z","modified":"2026-08-11T12:22:05Z","updated_at":"2026-11-02T18:02:00.294626Z"}],"ghsa":[{"id":"GHSA-9g63-gv45-4242","title":"In the kernel in Insyde InsydeH2O 5.x, certain SMM drivers did not correctly validate the...","description":"In the kernel in Insyde InsydeH2O 5.x, certain SMM drivers did not correctly validate the CommBuffer and CommBufferSize parameters, allowing callers to corrupt either the firmware or the OS memory. The fixed versions for this issue in the PnpSmm, SmmResourceCheckDxe, and BeepStatusCode drivers are 05.08.23, 05.16.23, 05.26.23, 05.35.23, 05.43.23, and 05.51.23 (for Kernel 5.0 through 5.5).","status":"published","published":"2022-05-24T19:16:22Z","modified":"2026-08-11T15:31:31Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-829"],"updated_at":"2026-11-02T15:10:17.025827Z"}],"nvd":[{"id":"CVE-2021-33626","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.","status":"published","published":"2021-10-01T03:15:06.593Z","modified":"2026-08-11T13:17:19.523Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"primary"},{"version":"2.0","score":4.6,"vector":"AV:L/AC:L/Au:N/C:P/I:P/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-829"],"updated_at":"2026-11-02T14:06:59.314106Z"}]}}