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Fencer Intel
high 7.5

CVE-2021-31340 json

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)…

published 5y ago modified 4mo ago also EUVD-2021-18250

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 62%
public exploits
0
none known

Summary

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.

Patch / fix

  • siemens simatic_rf166c_firmware 1.3.2
  • siemens simatic_rf185c_firmware 1.3.2
  • siemens simatic_rf186c_firmware 1.3.2
  • siemens simatic_rf186ci_firmware 1.3.2
  • siemens simatic_rf188c_firmware 1.3.2
  • siemens simatic_rf188ci_firmware 1.3.2
  • siemens simatic_rf360r_firmware 2.0
  • 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_cmiit_firmware 4.0
  • siemens simatic_reader_rf650r_etsi_firmware 4.0
  • siemens simatic_reader_rf650r_fcc_firmware 4.0
  • siemens simatic_reader_rf650r_arib_firmware 4.0
  • siemens simatic_reader_rf680r_cmiit_firmware 4.0
  • siemens simatic_reader_rf680r_etsi_firmware 4.0
  • siemens simatic_reader_rf680r_fcc_firmware 4.0

Is CVE-2021-31340 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-21-159-13 updated cvss 7.5

Siemens SIMATIC RFID (Update B)

  • Siemens SIMATIC Reader RF610R CMIIT >V3.0, <V4.0 Siemens SIMATIC Reader RF610R ETSI >V3.0, <V4.0 Siemens SIMATIC Reader RF610R FCC >V3.0, <V4.0 Siemens SIMATIC Reader RF615R CMIIT >V3.0, <V4.0 Siemens SIMATIC Reader RF615R ETSI >V3.0, <V4.0 Siemens SIMATIC Reader RF615R FCC >V3.0, <V4.0
    +12 more products
    Siemens SIMATIC Reader RF650R ARIB >V3.0, <V4.0 Siemens SIMATIC Reader RF650R CMIIT >V3.0, <V4.0 Siemens SIMATIC Reader RF650R ETSI >V3.0, <V4.0 Siemens SIMATIC Reader RF650R FCC >V3.0, <V4.0 Siemens SIMATIC Reader RF680R ARIB >V3.0, <V4.0 Siemens SIMATIC Reader RF680R CMIIT >V3.0, <V4.0 Siemens SIMATIC Reader RF680R ETSI >V3.0, <V4.0 Siemens SIMATIC Reader RF680R FCC >V3.0, <V4.0 Siemens SIMATIC Reader RF685R ARIB >V3.0, <V4.0 Siemens SIMATIC Reader RF685R CMIIT >V3.0, <V4.0 Siemens SIMATIC Reader RF685R ETSI >V3.0, <V4.0 Siemens SIMATIC Reader RF685R FCC >V3.0, <V4.0
    affected: fixed in V4.0, mitigation support.industry.siemens.com
  • Siemens SIMATIC RF166C >V1.1, <V1.3.2 Siemens SIMATIC RF185C >V1.1, <V1.3.2 Siemens SIMATIC RF186C >V1.1, <V1.3.2 Siemens SIMATIC RF186CI >V1.1, <V1.3.2 Siemens SIMATIC RF188C >V1.1, <V1.3.2 Siemens SIMATIC RF188CI >V1.1, <V1.3.2
    affected: fixed in V1.3.2, mitigation support.industry.siemens.com
  • Siemens SIMATIC RF360R <V2.0
    affected: fixed in V2.0, mitigation support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

Exploit prediction

0.99% chance of exploitation in the next 30 days, higher than 62% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Affected products

  • Siemens SIMATIC RF166C
  • Siemens SIMATIC RF185C
  • Siemens SIMATIC RF186C
  • Siemens SIMATIC RF186CI
  • Siemens SIMATIC RF188C
  • Siemens SIMATIC RF188CI
  • Siemens SIMATIC RF360R
  • Siemens SIMATIC Reader RF610R CMIIT
  • Siemens SIMATIC Reader RF610R ETSI
  • Siemens SIMATIC Reader RF610R FCC
  • Siemens SIMATIC Reader RF615R CMIIT
  • Siemens SIMATIC Reader RF615R ETSI
  • Siemens SIMATIC Reader RF615R FCC
  • Siemens SIMATIC Reader RF650R ARIB
  • Siemens SIMATIC Reader RF650R CMIIT
  • Siemens SIMATIC Reader RF650R ETSI
  • Siemens SIMATIC Reader RF650R FCC
  • Siemens SIMATIC Reader RF680R ARIB
  • Siemens SIMATIC Reader RF680R CMIIT
  • Siemens SIMATIC Reader RF680R ETSI
  • Siemens SIMATIC Reader RF680R FCC
  • Siemens SIMATIC Reader RF685R ARIB
  • Siemens SIMATIC Reader RF685R CMIIT
  • Siemens SIMATIC Reader RF685R ETSI
  • Siemens SIMATIC Reader RF685R FCC

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.