CVE-2021-31340

Name: CVE-2021-31340
Creator: NVD / NIST
Published: 2021-06-08T20:15:08.853+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 0.99%

Last modified Jun 17, 2026

CVE-2021-31340 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.99% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.99%

58.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Siemens	Simatic Rf166c Firmware	> 1.1, < 1.3.2
Siemens	Simatic Rf185c Firmware	> 1.1, < 1.3.2
Siemens	Simatic Rf186c Firmware	> 1.1, < 1.3.2
Siemens	Simatic Rf186ci Firmware	> 1.1, < 1.3.2
Siemens	Simatic Rf188c Firmware	> 1.1, < 1.3.2
Siemens	Simatic Rf188ci Firmware	> 1.1, < 1.3.2
Siemens	Simatic Rf360r Firmware	< 2.0
Siemens	Simatic Reader Rf610r Cmiit Firmware	>= 3.0, < 4.0
Siemens	Simatic Reader Rf610r Etsi Firmware	>= 3.0, < 4.0
Siemens	Simatic Reader Rf610r Fcc Firmware	>= 3.0, < 4.0
Siemens	Simatic Reader Rf615r Cmiit Firmware	>= 3.0, < 4.0
Siemens	Simatic Reader Rf615r Etsi Firmware	>= 3.0, < 4.0
Siemens	Simatic Reader Rf615r Fcc Firmware	>= 3.0, < 4.0
Siemens	Simatic Reader Rf650r Cmiit Firmware	>= 3.0, < 4.0
Siemens	Simatic Reader Rf650r Etsi Firmware	>= 3.0, < 4.0
Siemens	Simatic Reader Rf650r Fcc Firmware	>= 3.0, < 4.0
Siemens	Simatic Reader Rf650r Arib Firmware	>= 3.0, < 4.0
Siemens	Simatic Reader Rf680r Cmiit Firmware	>= 3.0, < 4.0
Siemens	Simatic Reader Rf680r Etsi Firmware	>= 3.0, < 4.0
Siemens	Simatic Reader Rf680r Fcc Firmware	>= 3.0, < 4.0
Siemens	Simatic Reader Rf680r Arib Firmware	>= 3.0, < 4.0
Siemens	Simatic Reader Rf685r Cmiit Firmware	>= 3.0, < 4.0
Siemens	Simatic Reader Rf685r Etsi Firmware	>= 3.0, < 4.0
Siemens	Simatic Reader Rf685r Fcc Firmware	>= 3.0, < 4.0
Siemens	Simatic Reader Rf685r Arib Firmware	>= 3.0, < 4.0

References

https://cert-portal.siemens.com/productcert/pdf/ssa-787292.pdfMitigation, Patch, Vendor Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-787292.pdfMitigation, Patch, Vendor Advisory

Timeline

Published: Jun 8, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-31340?

How severe is CVE-2021-31340?

CVE-2021-31340 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.99% probability of exploitation in the next 30 days.

How do I fix CVE-2021-31340?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-31340?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST