CVE-2021-37186

MEDIUM
5.4
CVSS Score
Published: September 14, 2021 at 10:47 AM UTC
Updated: June 17, 2026 at 04:00 AM UTC
12 products affected across 1 vendorLogo ! CMR2040 FirmwareLogo ! CMR2020 FirmwareSIMATIC RTU3041C Firmware

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Severity
MEDIUM5.4
Exploit prediction
EPSS 0.4%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Affected range stops below 2.2, so it looks safe — our inference, not a vendor statement
siemens-logo-cmr2020 (same device)
Affected range stops below 2.2, so it looks safe — our inference, not a vendor statement
siemens-logo-cmr2040 (same device)
Affected range stops below 4.0.9, so it looks safe — our inference, not a vendor statement
siemens-simatic-rtu3010c (same device)
Affected range stops below 4.0.9, so it looks safe — our inference, not a vendor statement
siemens-simatic-rtu3030c (same device)
Affected range stops below 4.0.9, so it looks safe — our inference, not a vendor statement
siemens-simatic-rtu3031c (same device)
Affected range stops below 4.0.9, so it looks safe — our inference, not a vendor statement
siemens-simatic-rtu3041c (same device)
All versions
All versions
All versions
All versions

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

CVSS

Attack Vector
ADJACENT_NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-330

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