CVE-2021-31345Network attack vector

Information disclosure via unchecked UDP payload length

Published Nov 9, 2021 · Updated Mar 11, 2025

Improper UDP input validation in Siemens Capital Embedded AR Classic and PLUSCONTROL 1st Gen allows remote attackers to disclose information. The Nucleus NET stack trusts the total UDP payload length declared in the IP header instead of checking it before user-defined UDP applications process the payload. Exploitation requires network reachability to such an application; resulting effects depend on that application and include information disclosure and service interruption.

CVSS severity7.5
High
EPSS probability1.63%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper UDP input validation in Siemens Capital Embedded AR Classic and PLUSCONTROL 1st Gen allows remote attackers to disclose information. The Nucleus NET stack trusts the total UDP payload length declared in the IP header instead of checking it before user-defined UDP applications process the payload. Exploitation requires network reachability to such an application; resulting effects depend on that application and include information disclosure and service interruption.

The record

CVE
CVE-2021-31345
Published
Nov 9, 2021
Updated
Mar 11, 2025
Vendor
Siemens
Product
Capital Embedded AR Classic
Classifications
CWE-1284, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 9, 2021CVE publishedPublication date reported by the CVE source.
  2. Mar 11, 2025Record 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=0 <*
  2. Affected versionversion=0 <V2303

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Siemens · Capital Embedded AR Classicversion=0 <*; version=0 <V2303
Siemens · PLUSCONTROL 1st Genversion=All versions

Published CVSS scores

6.4NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:P
7.5Siemens AGCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1284Improper Validation of Specified Quantity in Input
T1499.004Application or System Exploitation

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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