CVE-2021-33716

Sensitive information disclosure from cleartext storage

Published Sep 14, 2021 · Updated Aug 3, 2024

Cleartext storage in Siemens SIMATIC CP 1543-1 before 3.0 and CP 1545-1 before 1.1 allows remote attackers to read sensitive data. Siemens states that the communication processors store retrievable information without encryption but does not identify the storage locus or retrieval request. Access to the affected device's subnet is required, and the reported consequence is disclosure without modification or service interruption.

CVSS severity6.5
Medium
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cleartext storage in Siemens SIMATIC CP 1543-1 before 3.0 and CP 1545-1 before 1.1 allows remote attackers to read sensitive data. Siemens states that the communication processors store retrievable information without encryption but does not identify the storage locus or retrieval request. Access to the affected device's subnet is required, and the reported consequence is disclosure without modification or service interruption.

The record

CVE
CVE-2021-33716
Published
Sep 14, 2021
Updated
Aug 3, 2024
Vendor
Siemens
Product
SIMATIC CP 1543-1
Classifications
CWE-312, T0866
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 14, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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 < V3.0

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Siemens · SIMATIC CP 1543-1version=All versions < V3.0
Siemens · SIMATIC CP 1545-1version=All versions < V1.1

Published CVSS scores

3.3NVDAV:A/AC:L/Au:N/C:P/I:N/A:N
6.5NVDCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

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.

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No observations available

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

Weakness, pattern, technique

CWE-312Cleartext Storage of Sensitive Information
T0866Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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