{"id":"CVE-2020-27632","aliases":["EUVD-2020-20139","GHSA-53pq-r3c7-x97x"],"status":"published","title":"In SIMATIC MV400 family versions prior to v7.0.6, the ISN generator is initialized with a...","description":"In SIMATIC MV400 family versions prior to v7.0.6, the ISN generator is initialized with a constant value and has constant increments. An attacker could predict and hijack TCP sessions.","severity":{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-09","score":0.02139,"percentile":0.82162,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"published":"2021-03-10T00:00:00Z","modified":"2026-06-17T03:09:24Z","products":[{"vendor":"siemens","product":"simatic_mv420_firmware"},{"vendor":"siemens","product":"simatic_mv440_firmware"}],"references":[{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-599268.pdf","tags":["x_transferred","Vendor Advisory"]},{"url":"https://www.cisa.gov/news-events/ics-advisories/icsa-21-042-01","tags":["x_transferred"]},{"url":"https://www.forescout.com/resources/numberjack-weak-isn-generation-in-embedded-tcpip-stacks/","tags":["x_transferred"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2020-27632"},{"url":"https://github.com/advisories/GHSA-53pq-r3c7-x97x"}],"sources":{"cve":[{"id":"CVE-2020-27632","description":"In SIMATIC MV400 family versions prior to v7.0.6, the ISN generator is initialized with a constant value and has constant increments. An attacker could predict and hijack TCP sessions.","status":"published","published":"2021-03-10T00:00:00Z","modified":"2024-08-04T16:18:45.486Z","updated_at":"2026-11-02T14:35:53.552996Z"}],"euvd":[{"id":"EUVD-2020-20139","description":"In SIMATIC MV400 family versions prior to v7.0.6, the ISN generator is initialized with a constant value and has constant increments. An attacker could predict and hijack TCP sessions.","status":"published","published":"2021-03-10T00:00:00Z","modified":"2024-08-04T16:18:45Z","updated_at":"2026-11-03T03:07:12.435876Z"}],"ghsa":[{"id":"GHSA-53pq-r3c7-x97x","title":"In SIMATIC MV400 family versions prior to v7.0.6, the ISN generator is initialized with a...","description":"In SIMATIC MV400 family versions prior to v7.0.6, the ISN generator is initialized with a constant value and has constant increments. An attacker could predict and hijack TCP sessions.","status":"published","published":"2022-05-24T17:44:03Z","modified":"2023-10-19T05:04:16Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high"}],"updated_at":"2026-11-02T14:54:48.16134Z"}],"nvd":[{"id":"CVE-2020-27632","description":"In SIMATIC MV400 family versions prior to v7.0.6, the ISN generator is initialized with a constant value and has constant increments. An attacker could predict and hijack TCP sessions.","status":"published","published":"2021-03-10T18:15:12.797Z","modified":"2026-06-17T03:09:24.01Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high","assessor":"primary"},{"version":"2.0","score":5,"vector":"AV:N/AC:L/Au:N/C:N/I:P/A:N","level":"medium","assessor":"primary"}],"updated_at":"2026-11-02T14:06:37.687844Z"}]}}