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Fencer Vulns
high 7.5

CVE-2020-28400 json

Affected devices contain a vulnerability that allows an unauthenticated attacker to trigger a denial of service condition.

published 2021-07-13 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-20859

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.9%
EPSS 1.9% chance of exploitation in 30 days, percentile 79%
public exploits
0
none known

Summary

Affected devices contain a vulnerability that allows an unauthenticated attacker to trigger a denial of service condition. The vulnerability can be triggered if a large amount of DCP reset packets are sent to the device.

Patch / fix

  • Siemens Development/Evaluation Kits for PROFINET IO: EK-ERTEC 200P V4.7
  • Siemens RUGGEDCOM RM1224 LTE(4G) EU V6.4
  • Siemens RUGGEDCOM RM1224 LTE(4G) NAM V6.4
  • Siemens SCALANCE M804PB V6.4
  • Siemens SCALANCE M812-1 ADSL-Router V6.4
  • Siemens SCALANCE M816-1 ADSL-Router V6.4
  • Siemens SCALANCE M826-2 SHDSL-Router V6.4
  • Siemens SCALANCE M874-2 V6.4
  • Siemens SCALANCE M874-3 V6.4
  • Siemens SCALANCE M874-3 3G-Router (CN) V6.4
  • Siemens SCALANCE M876-3 V6.4
  • Siemens SCALANCE M876-3 (ROK) V6.4
  • Siemens SCALANCE M876-4 V6.4
  • Siemens SCALANCE M876-4 (EU) V6.4
  • Siemens SCALANCE M876-4 (NAM) V6.4
  • Siemens SCALANCE MUM853-1 (A1) V6.4
  • Siemens SCALANCE MUM853-1 (B1) V6.4
  • Siemens SCALANCE MUM853-1 (EU) V6.4
  • Siemens SCALANCE MUM856-1 (A1) V6.4
  • Siemens SCALANCE MUM856-1 (B1) V6.4
  • Siemens SCALANCE MUM856-1 (CN) V6.4
  • Siemens SCALANCE MUM856-1 (EU) V6.4
  • Siemens SCALANCE MUM856-1 (RoW) V6.4
  • Siemens SCALANCE S615 EEC LAN-Router V6.4
  • Siemens SCALANCE S615 LAN-Router V6.4
  • Siemens SCALANCE W1748-1 M12 V3.0.0
  • Siemens SCALANCE W1788-1 M12 V3.0.0
  • Siemens SCALANCE W1788-2 EEC M12 V3.0.0
  • Siemens SCALANCE W1788-2 M12 V3.0.0
  • Siemens SCALANCE W1788-2IA M12 V3.0.0

Vendor advisories

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

cisa ICSA-21-194-03 updated cvss 7.5

Siemens PROFINET Devices

  • Siemens Development/Evaluation Kits for PROFINET IO: DK Standard Ethernet Controller Siemens Development/Evaluation Kits for PROFINET IO: EK-ERTEC 200
    affected: mitigation, no fix planned
  • Siemens Development/Evaluation Kits for PROFINET IO: EK-ERTEC 200P < 4.7
    affected: fixed in V4.7, mitigation support.industry.siemens.com
  • Siemens RUGGEDCOM RM1224 LTE(4G) EU (6GK6108-4AM00-2BA2) < 6.4 Siemens RUGGEDCOM RM1224 LTE(4G) NAM (6GK6108-4AM00-2DA2) < 6.4 Siemens SCALANCE M804PB (6GK5804-0AP00-2AA2) < 6.4 Siemens SCALANCE M812-1 ADSL-Router (6GK5812-1AA00-2AA2) < 6.4 Siemens SCALANCE M812-1 ADSL-Router (6GK5812-1BA00-2AA2) < 6.4 Siemens SCALANCE M816-1 ADSL-Router (6GK5816-1AA00-2AA2) < 6.4
    +20 more products
    Siemens SCALANCE M816-1 ADSL-Router (6GK5816-1BA00-2AA2) < 6.4 Siemens SCALANCE M826-2 SHDSL-Router (6GK5826-2AB00-2AB2) < 6.4 Siemens SCALANCE M874-2 (6GK5874-2AA00-2AA2) < 6.4 Siemens SCALANCE M874-3 (6GK5874-3AA00-2AA2) < 6.4 Siemens SCALANCE M874-3 3G-Router (CN) (6GK5874-3AA00-2FA2) < 6.4 Siemens SCALANCE M876-3 (6GK5876-3AA02-2BA2) < 6.4 Siemens SCALANCE M876-3 (ROK) (6GK5876-3AA02-2EA2) < 6.4 Siemens SCALANCE M876-4 (6GK5876-4AA10-2BA2) < 6.4 Siemens SCALANCE M876-4 (EU) (6GK5876-4AA00-2BA2) < 6.4 Siemens SCALANCE M876-4 (NAM) (6GK5876-4AA00-2DA2) < 6.4 Siemens SCALANCE MUM853-1 (A1) (6GK5853-2EA10-2AA1) < 6.4 Siemens SCALANCE MUM853-1 (B1) (6GK5853-2EA10-2BA1) < 6.4 Siemens SCALANCE MUM853-1 (EU) (6GK5853-2EA00-2DA1) < 6.4 Siemens SCALANCE MUM856-1 (A1) (6GK5856-2EA10-3AA1) < 6.4 Siemens SCALANCE MUM856-1 (B1) (6GK5856-2EA10-3BA1) < 6.4 Siemens SCALANCE MUM856-1 (CN) (6GK5856-2EA00-3FA1) < 6.4 Siemens SCALANCE MUM856-1 (EU) (6GK5856-2EA00-3DA1) < 6.4 Siemens SCALANCE MUM856-1 (RoW) (6GK5856-2EA00-3AA1) < 6.4 Siemens SCALANCE S615 EEC LAN-Router (6GK5615-0AA01-2AA2) < 6.4 Siemens SCALANCE S615 LAN-Router (6GK5615-0AA00-2AA2) < 6.4
    affected: fixed in V6.4, mitigation support.industry.siemens.com
  • Siemens SCALANCE W721-1 RJ45 (6GK5721-1FC00-0AA0) < 6.4.0 Siemens SCALANCE W721-1 RJ45 (6GK5721-1FC00-0AB0) < 6.4.0 Siemens SCALANCE W722-1 RJ45 (6GK5722-1FC00-0AA0) < 6.4.0 Siemens SCALANCE W722-1 RJ45 (6GK5722-1FC00-0AB0) < 6.4.0 Siemens SCALANCE W722-1 RJ45 (6GK5722-1FC00-0AC0) < 6.4.0 Siemens SCALANCE W734-1 RJ45 (6GK5734-1FX00-0AA0) < 6.4.0
    +5 more products
    Siemens SCALANCE W734-1 RJ45 (6GK5734-1FX00-0AA6) < 6.4.0 Siemens SCALANCE W734-1 RJ45 (6GK5734-1FX00-0AB0) < 6.4.0 Siemens SCALANCE W734-1 RJ45 (USA) (6GK5734-1FX00-0AB6) < 6.4.0 Siemens SCALANCE W738-1 M12 (6GK5738-1GY00-0AA0) < 6.4.0 Siemens SCALANCE W738-1 M12 (6GK5738-1GY00-0AB0) < 6.4.0
    affected: fixed in V6.4.0, mitigation support.industry.siemens.com

316 more affected in the full advisory

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

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
2 y ago

Exploit prediction

1.86% chance of exploitation in the next 30 days, higher than 79% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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 Development/Evaluation Kits for PROFINET IO: DK Standard Ethernet Controller
  • Siemens Development/Evaluation Kits for PROFINET IO: EK-ERTEC 200
  • Siemens Development/Evaluation Kits for PROFINET IO: EK-ERTEC 200P
  • Siemens RUGGEDCOM RM1224 LTE(4G) EU
  • Siemens RUGGEDCOM RM1224 LTE(4G) NAM
  • Siemens SCALANCE M804PB
  • Siemens SCALANCE M812-1 ADSL-Router
  • Siemens SCALANCE M816-1 ADSL-Router
  • Siemens SCALANCE M826-2 SHDSL-Router
  • Siemens SCALANCE M874-2
  • Siemens SCALANCE M874-3
  • Siemens SCALANCE M874-3 3G-Router (CN)
  • Siemens SCALANCE M876-3
  • Siemens SCALANCE M876-3 (ROK)
  • Siemens SCALANCE M876-4
  • Siemens SCALANCE M876-4 (EU)
  • Siemens SCALANCE M876-4 (NAM)
  • Siemens SCALANCE MUM853-1 (A1)
  • Siemens SCALANCE MUM853-1 (B1)
  • Siemens SCALANCE MUM853-1 (EU)
  • Siemens SCALANCE MUM856-1 (A1)
  • Siemens SCALANCE MUM856-1 (B1)
  • Siemens SCALANCE MUM856-1 (CN)
  • Siemens SCALANCE MUM856-1 (EU)
  • Siemens SCALANCE MUM856-1 (RoW)
  • Siemens SCALANCE S615 EEC LAN-Router
  • Siemens SCALANCE S615 LAN-Router
  • Siemens SCALANCE W1748-1 M12
  • Siemens SCALANCE W1788-1 M12
  • Siemens SCALANCE W1788-2 EEC M12
  • Siemens SCALANCE W1788-2 M12
  • Siemens SCALANCE W1788-2IA M12
  • Siemens SCALANCE W721-1 RJ45
  • Siemens SCALANCE W722-1 RJ45
  • Siemens SCALANCE W734-1 RJ45
  • Siemens SCALANCE W734-1 RJ45 (USA)
  • Siemens SCALANCE W738-1 M12
  • Siemens SCALANCE W748-1 M12
  • Siemens SCALANCE W748-1 RJ45
  • Siemens SCALANCE W761-1 RJ45
  • Siemens SCALANCE W774-1 M12 EEC
  • Siemens SCALANCE W774-1 RJ45
  • Siemens SCALANCE W774-1 RJ45 (USA)
  • Siemens SCALANCE W778-1 M12
  • Siemens SCALANCE W778-1 M12 EEC
  • Siemens SCALANCE W778-1 M12 EEC (USA)
  • Siemens SCALANCE W786-1 RJ45
  • Siemens SCALANCE W786-2 RJ45
  • Siemens SCALANCE W786-2 SFP
  • Siemens SCALANCE W786-2IA RJ45

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling

References

Sources

Fencer Vulns 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.