{"id":"CVE-2021-37186","aliases":["EUVD-2021-23760","GHSA-5g5j-x767-23r3"],"status":"published","title":"A vulnerability has been identified in LOGO! CMR2020 (All versions \u003c V2.2), LOGO! CMR2040 (All...","description":"A vulnerability has been identified in LOGO! CMR2020 (All versions \u003c V2.2), LOGO! CMR2040 (All versions \u003c V2.2), SIMATIC RTU3010C (All versions \u003c V4.0.9), SIMATIC RTU3030C (All versions \u003c V4.0.9), SIMATIC RTU3031C (All versions \u003c V4.0.9), SIMATIC RTU3041C (All versions \u003c V4.0.9). The underlying TCP/IP stack does not properly calculate the random numbers used as ISN (Initial Sequence Numbers). An adjacent attacker with network access to the LAN interface could interfere with traffic, spoof the connection and gain access to sensitive information.","severity":{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-12","score":0.00356,"percentile":0.29786,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-330"],"published":"2021-09-14T10:47:49Z","modified":"2026-06-17T04:00:13Z","products":[{"vendor":"siemens","product":"logo! cmr2020"},{"vendor":"siemens","product":"logo! cmr2040"},{"vendor":"siemens","product":"logo\\!_cmr2020_firmware"},{"vendor":"siemens","product":"logo\\!_cmr2040_firmware"},{"vendor":"siemens","product":"simatic rtu3010c"},{"vendor":"siemens","product":"simatic rtu3030c"},{"vendor":"siemens","product":"simatic rtu3031c"},{"vendor":"siemens","product":"simatic rtu3041c"},{"vendor":"siemens","product":"simatic_rtu3010c_firmware"},{"vendor":"siemens","product":"simatic_rtu3030c_firmware"},{"vendor":"siemens","product":"simatic_rtu3031c_firmware"},{"vendor":"siemens","product":"simatic_rtu3041c_firmware"}],"references":[{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-316383.pdf","tags":["x_refsource_MISC","x_transferred","Patch","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-37186"},{"url":"https://github.com/advisories/GHSA-5g5j-x767-23r3"}],"sources":{"cve":[{"id":"CVE-2021-37186","description":"A vulnerability has been identified in LOGO! CMR2020 (All versions \u003c V2.2), LOGO! CMR2040 (All versions \u003c V2.2), SIMATIC RTU3010C (All versions \u003c V4.0.9), SIMATIC RTU3030C (All versions \u003c V4.0.9), SIMATIC RTU3031C (All versions \u003c V4.0.9), SIMATIC RTU3041C (All versions \u003c V4.0.9). The underlying TCP/IP stack does not properly calculate the random numbers used as ISN (Initial Sequence Numbers). An adjacent attacker with network access to the LAN interface could interfere with traffic, spoof the connection and gain access to sensitive information.","status":"published","published":"2021-09-14T10:47:49Z","modified":"2024-08-04T01:16:03.873Z","cwes":["CWE-330"],"updated_at":"2026-11-02T14:32:58.359368Z"}],"euvd":[{"id":"EUVD-2021-23760","description":"A vulnerability has been identified in LOGO! CMR2020 (All versions \u003c V2.2), LOGO! CMR2040 (All versions \u003c V2.2), SIMATIC RTU3010C (All versions \u003c V4.0.9), SIMATIC RTU3030C (All versions \u003c V4.0.9), SIMATIC RTU3031C (All versions \u003c V4.0.9), SIMATIC RTU3041C (All versions \u003c V4.0.9). The underlying TCP/IP stack does not properly calculate the random numbers used as ISN (Initial Sequence Numbers). An adjacent attacker with network access to the LAN interface could interfere with traffic, spoof the connection and gain access to sensitive information.","status":"published","published":"2021-09-14T10:47:49Z","modified":"2024-08-04T01:16:03Z","updated_at":"2026-11-03T03:24:28.314716Z"}],"ghsa":[{"id":"GHSA-5g5j-x767-23r3","title":"A vulnerability has been identified in LOGO! CMR2020 (All versions \u003c V2.2), LOGO! CMR2040 (All...","description":"A vulnerability has been identified in LOGO! CMR2020 (All versions \u003c V2.2), LOGO! CMR2040 (All versions \u003c V2.2), SIMATIC RTU 3000 family (All versions). The underlying TCP/IP stack does not properly calculate the random numbers used as ISN (Initial Sequence Numbers). An adjacent attacker with network access to the LAN interface could interfere with traffic, spoof the connection and gain access to sensitive information.","status":"published","published":"2022-05-24T19:14:30Z","modified":"2023-01-30T05:02:06Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-330"],"updated_at":"2026-11-02T14:46:33.666288Z"}],"nvd":[{"id":"CVE-2021-37186","description":"A vulnerability has been identified in LOGO! CMR2020 (All versions \u003c V2.2), LOGO! CMR2040 (All versions \u003c V2.2), SIMATIC RTU3010C (All versions \u003c V4.0.9), SIMATIC RTU3030C (All versions \u003c V4.0.9), SIMATIC RTU3031C (All versions \u003c V4.0.9), SIMATIC RTU3041C (All versions \u003c V4.0.9). The underlying TCP/IP stack does not properly calculate the random numbers used as ISN (Initial Sequence Numbers). An adjacent attacker with network access to the LAN interface could interfere with traffic, spoof the connection and gain access to sensitive information.","status":"published","published":"2021-09-14T11:15:25.85Z","modified":"2026-06-17T04:00:13.147Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","level":"medium","assessor":"primary"},{"version":"2.0","score":4.8,"vector":"AV:A/AC:L/Au:N/C:P/I:P/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-330"],"updated_at":"2026-11-02T14:06:58.502206Z"}]}}