Cyber Resilience

CVE-2021-37186

Medium

Published: 14 September 2021

Published
14 September 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 5.4 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
EPSS Score 0.0016 37.3th percentile
Risk Priority 11 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-37186 is a medium-severity Use of Insufficiently Random Values (CWE-330) vulnerability in Siemens Logo\! Cmr2020 Firmware. Its CVSS base score is 5.4 (Medium).

Operationally, ranked at the 37.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

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…

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< 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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

siemens
logo\! cmr2020 firmware
≤ 2.2
siemens
logo\! cmr2040 firmware
≤ 2.2
siemens
simatic rtu3010c firmware
≤ 4.0.9
siemens
simatic rtu3030c firmware
≤ 4.0.9
siemens
simatic rtu3031c firmware
≤ 4.0.9
siemens
simatic rtu3041c firmware
≤ 4.0.9

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-330

Key generation under controlled management uses approved random-bit sources rather than insufficiently random values.

References