CVE-2020-25241Network attack vector

Remote TCP session termination via invalid RST sequence

Published Mar 15, 2021 · Updated Aug 4, 2024

Improper input validation in Siemens SIMATIC MV400 family before V7.0.6 allows remote attackers to terminate arbitrary TCP sessions. The underlying TCP stack accepts incoming TCP RST packets without correctly validating their sequence numbers, so spoofed or crafted resets can tear down sessions that the attacker does not own. Exploitation requires network reachability to the reader; the bounded impact is interruption of TCP communications rather than disclosed data access or code execution.

CVSS severity7.5
High
EPSS probability1.03%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Siemens SIMATIC MV400 family before V7.0.6 allows remote attackers to terminate arbitrary TCP sessions. The underlying TCP stack accepts incoming TCP RST packets without correctly validating their sequence numbers, so spoofed or crafted resets can tear down sessions that the attacker does not own. Exploitation requires network reachability to the reader; the bounded impact is interruption of TCP communications rather than disclosed data access or code execution.

The record

CVE
CVE-2020-25241
Published
Mar 15, 2021
Updated
Aug 4, 2024
Vendor
Siemens
Product
SIMATIC MV400 family
Classifications
CWE-1285, CWE-129, T1498
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 15, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=All Versions < V7.0.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Siemens · SIMATIC MV400 familyversion=All Versions < V7.0.6

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1285Improper Validation of Specified Quantity in Input
CWE-129Improper Validation of Array Index
T1498Network Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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