{"cve":"CVE-2021-37186","nvd":{"published":"2021-09-14T11:15:25.850","modified":"2026-06-17T04:00:13.147","status":"Modified","description":"A vulnerability has been identified in LOGO! CMR2020 (All versions < V2.2), LOGO! CMR2040 (All versions < V2.2), SIMATIC RTU3010C (All versions < V4.0.9), SIMATIC RTU3030C (All versions < V4.0.9), SIMATIC RTU3031C (All versions < V4.0.9), SIMATIC RTU3041C (All versions < 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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","score":5.4},"cwes":["CWE-330"],"references":["https://cert-portal.siemens.com/productcert/pdf/ssa-316383.pdf","https://cert-portal.siemens.com/productcert/pdf/ssa-316383.pdf"],"products":["siemens:logo\\!_cmr2020_firmware","siemens:logo\\!_cmr2040_firmware","siemens:simatic_rtu3010c_firmware","siemens:simatic_rtu3030c_firmware","siemens:simatic_rtu3031c_firmware","siemens:simatic_rtu3041c_firmware"],"source":"nvd","synced_at":"2026-10-19T21:23:41.316049955+00:00"},"epss":{"cve":"CVE-2021-37186","score":0.00356,"percentile":0.29369,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}