A vulnerability has been identified in SIMATIC MV400 family (All Versions < V7.0.6).

published 2021-03-15 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-17931

cvss: 7.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.1%; EPSS 1.1% chance of exploitation in 30 days, percentile 65%
public exploits: 0; none known

A vulnerability has been identified in SIMATIC MV400 family (All Versions < V7.0.6). The underlying TCP stack of the affected products does not correctly validate the sequence number for incoming TCP RST packages. An attacker could exploit this to terminate arbitrary TCP sessions.

Patch / fix

fixed in 7

siemens simatic_mv440_sr_firmware 7.0.6
siemens simatic_mv440_hr_firmware 7.0.6
siemens simatic_mv440_ur_firmware 7.0.6
siemens simatic_mv420_sr-b_firmware 7.0.6
siemens simatic_mv420_sr-p_firmware 7.0.6
siemens simatic_mv420_sr-b_body_firmware 7.0.6
siemens simatic_mv420_sr-p_body_firmware 7.0.6

Vendor advisories

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

cisa ICSA-21-068-07 updated 2021-03-09 cvss 7.5

Siemens TCP Stack of SIMATIC MV400

Siemens SIMATIC MV400 family <V7.0.6
affected: fixed in V7.0.6

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

Exploit prediction

1.07% chance of exploitation in the next 30 days, higher than 65% of all scored CVEs (FIRST EPSS, 2026-11-08).

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 MV400 family

Classification

Weakness

CWE-1285 Improper Validation of Specified Index, Position, or Offset in Input
CWE-129 Improper Validation of Array Index

References

cert-portal.siemens.com /productcert/pdf/ssa-599268.pdf
vendor-advisory

Sources

CVE List CVE-2020-25241
NVD CVE-2020-25241

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.

Summary