CVE-2021-31340

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-06-08 · updated 2026-06-17
Weakness: CWE-400

Description

A vulnerability has been identified in SIMATIC RF166C (All versions > V1.1 and < V1.3.2), SIMATIC RF185C (All versions > V1.1 and < V1.3.2), SIMATIC RF186C (All versions > V1.1 and < V1.3.2), SIMATIC RF186CI (All versions > V1.1 and < V1.3.2), SIMATIC RF188C (All versions > V1.1 and < V1.3.2), SIMATIC RF188CI (All versions > V1.1 and < V1.3.2), SIMATIC RF360R (All versions < V2.0), SIMATIC Reader RF610R CMIIT (All versions > V3.0 < V4.0), SIMATIC Reader RF610R ETSI (All versions > V3.0 < V4.0), SIMATIC Reader RF610R FCC (All versions > V3.0 < V4.0), SIMATIC Reader RF615R CMIIT (All versions > V3.0 < V4.0), SIMATIC Reader RF615R ETSI (All versions > V3.0 < V4.0), SIMATIC Reader RF615R FCC (All versions > V3.0 < V4.0), SIMATIC Reader RF650R ARIB (All versions > V3.0 < V4.0), SIMATIC Reader RF650R CMIIT (All versions > V3.0 < V4.0), SIMATIC Reader RF650R ETSI (All versions > V3.0 < V4.0), SIMATIC Reader RF650R FCC (All versions > V3.0 < V4.0), SIMATIC Reader RF680R ARIB (All versions > V3.0 < V4.0), SIMATIC Reader RF680R CMIIT (All versions > V3.0 < V4.0), SIMATIC Reader RF680R ETSI (All versions > V3.0 < V4.0), SIMATIC Reader RF680R FCC (All versions > V3.0 < V4.0), SIMATIC Reader RF685R ARIB (All versions > V3.0 < V4.0), SIMATIC Reader RF685R CMIIT (All versions > V3.0 < V4.0), SIMATIC Reader RF685R ETSI (All versions > V3.0 < V4.0), SIMATIC Reader RF685R FCC (All versions > V3.0 < V4.0). Affected devices do not properly handle large numbers of incoming connections. An attacker may leverage this to cause a Denial-of-Service situation.

Affected products

Siemens Simatic Reader Rf610R Cmiit Firmware: from 3.0 before 4.0 — fixed in 4.0
Siemens Simatic Reader Rf610R Etsi Firmware: from 3.0 before 4.0 — fixed in 4.0
Siemens Simatic Reader Rf610R Fcc Firmware: from 3.0 before 4.0 — fixed in 4.0
Siemens Simatic Reader Rf615R Cmiit Firmware: from 3.0 before 4.0 — fixed in 4.0
Siemens Simatic Reader Rf615R Etsi Firmware: from 3.0 before 4.0 — fixed in 4.0
Siemens Simatic Reader Rf615R Fcc Firmware: from 3.0 before 4.0 — fixed in 4.0
Siemens Simatic Reader Rf650R Arib Firmware: from 3.0 before 4.0 — fixed in 4.0
Siemens Simatic Reader Rf650R Cmiit Firmware: from 3.0 before 4.0 — fixed in 4.0
Siemens Simatic Reader Rf650R Etsi Firmware: from 3.0 before 4.0 — fixed in 4.0
Siemens Simatic Reader Rf650R Fcc Firmware: from 3.0 before 4.0 — fixed in 4.0
Siemens Simatic Reader Rf680R Arib Firmware: from 3.0 before 4.0 — fixed in 4.0
Siemens Simatic Reader Rf680R Cmiit Firmware: from 3.0 before 4.0 — fixed in 4.0
Siemens Simatic Reader Rf680R Etsi Firmware: from 3.0 before 4.0 — fixed in 4.0
Siemens Simatic Reader Rf680R Fcc Firmware: from 3.0 before 4.0 — fixed in 4.0
Siemens Simatic Reader Rf685R Arib Firmware: from 3.0 before 4.0 — fixed in 4.0
Siemens Simatic Reader Rf685R Cmiit Firmware: from 3.0 before 4.0 — fixed in 4.0
Siemens Simatic Reader Rf685R Etsi Firmware: from 3.0 before 4.0 — fixed in 4.0
Siemens Simatic Reader Rf685R Fcc Firmware: from 3.0 before 4.0 — fixed in 4.0
Siemens Simatic Rf166C Firmware: from 1.1 (excl.) before 1.3.2 — fixed in 1.3.2
Siemens Simatic Rf185C Firmware: from 1.1 (excl.) before 1.3.2 — fixed in 1.3.2
Siemens Simatic Rf186C Firmware: from 1.1 (excl.) before 1.3.2 — fixed in 1.3.2
Siemens Simatic Rf186Ci Firmware: from 1.1 (excl.) before 1.3.2 — fixed in 1.3.2
Siemens Simatic Rf188C Firmware: from 1.1 (excl.) before 1.3.2 — fixed in 1.3.2
Siemens Simatic Rf188Ci Firmware: from 1.1 (excl.) before 1.3.2 — fixed in 1.3.2
Siemens Simatic Rf360R Firmware: before 2.0 — fixed in 2.0

How to fix

Upgrade to a fixed version: Siemens Simatic Reader Rf610R Cmiit Firmware 4.0; Siemens Simatic Reader Rf610R Etsi Firmware 4.0; Siemens Simatic Reader Rf610R Fcc Firmware 4.0; Siemens Simatic Reader Rf615R Cmiit Firmware 4.0; Siemens Simatic Reader Rf615R Etsi Firmware 4.0; Siemens Simatic Reader Rf615R Fcc Firmware 4.0; Siemens Simatic Reader Rf650R Arib Firmware 4.0; Siemens Simatic Reader Rf650R Cmiit Firmware 4.0; Siemens Simatic Reader Rf650R Etsi Firmware 4.0; Siemens Simatic Reader Rf650R Fcc Firmware 4.0; Siemens Simatic Reader Rf680R Arib Firmware 4.0; Siemens Simatic Reader Rf680R Cmiit Firmware 4.0. Check the vendor advisory for mitigations.

References

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