CVE-2021-33716

lowpriority · track · 26OT risk · elevatedEPSS 0.003 · 17 %ileDEEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.25% (17th) EPSS

CVSS 3.3 · low

Is it mine?

10 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · cisa_csaf_ot · nvd

EPSS · scored 2026-10-27

A vulnerability has been identified in SIMATIC CP 1543-1 (incl. SIPLUS variants) (All versions < V3.0), SIMATIC CP 1545-1 (All versions < V1.1). An attacker with access to the subnet of the affected device could retrieve sensitive information stored in cleartext.

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

FixedSIMATIC CP 1543-1 (incl. SIPLUS variants)siemens_psirt
After migrating the project successfully, compilation and download to the device is required.
https://support.industry.siemens.com/cs/ww/en/view/109800773/
FixedSIMATIC CP 1545-1siemens_psirt
Update to V1.1 or later version
https://support.industry.siemens.com/cs/ww/en/view/109811116/
FixedSIMATIC CP 1543-1 (incl. SIPLUS variants)cisa_csaf_ot
After migrating the project successfully, compilation and download to the device is required.
https://support.industry.siemens.com/cs/ww/en/view/109800773/
FixedSIMATIC CP 1545-1cisa_csaf_ot
Update to V1.1 or later version
https://support.industry.siemens.com/cs/ww/en/view/109811116/

cvss

Technical severity, 0–10. One row per scoring source.

6.5

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 3.3–6.5

v2.03.3lowAV:A/AC:L/Au:N/C:P/I:N/A:Nprimary · NVD / NIST USexploitability 6.5 · impact 2.9

v3.16.5mediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Nprimary · NVD / NIST USexploitability 2.8 · impact 3.6

v3.16.5mediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:P/RL:O/RC:Csecondary · CISA US

v3.16.5mediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:P/RL:O/RC:Csecondary · Siemens ProductCERT DE

v3.16mediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-312USprimaryCWE-312USCWE-312US

affected products (10)

Products and version ranges known to be affected.

SIMATIC CP 1543-1 (incl. SIPLUS variants)all versionscisa_csaf_otUS
SIMATIC CP 1545-1all versionscisa_csaf_otUS
Siemens SIMATIC CP 1543-1 (incl. SIPLUS variants)< V3.0cisa_csaf_otUS
Siemens SIMATIC CP 1545-1< V1.1cisa_csaf_otUS
Siemens SIMATIC CP 1543-1 (incl. SIPLUS variants)All versions → V3.0enisa_euvdEU
Siemens SIMATIC CP 1545-1All versions → V1.1enisa_euvdEU
siemens simatic cp 1543-1 firmware< 3.0nvdUScpe:2.3:o:siemens:simatic_cp_1543-1_firmware:*:*:*:*:*:*:*:*
siemens simatic cp 1545-1 firmware< 1.1nvdUScpe:2.3:o:siemens:simatic_cp_1545-1_firmware:*:*:*:*:*:*:*:*
Siemens SIMATIC CP 1543-1 (incl. SIPLUS variants)< V3.0siemens_psirtDE
Siemens SIMATIC CP 1545-1< V1.1siemens_psirtDE

advisories (2)

Vendor and ecosystem advisories describing this.

SSA-535997SSA-535997: Cleartext Storage of Sensitive Information in Multiple SIMATIC Products2021-09-14csaf · siemens_psirtDE
A cleartext vulnerability was found in the SIMATIC communication processors CP 1543-1 and CP 1545-1 that could allow an attacker to read sensitive information. Siemens has released updates for the affected products and recommends to update to the latest versions.
ICSA-21-257-06Siemens SIMATIC CP (Update A)2021-09-14icsa · cisa_csaf_otUS
A cleartext vulnerability was found in the SIMATIC communication processors CP 1543-1 and CP 1545-1 that could allow an attacker to read sensitive information. Siemens has released updates for the affected products and recommends to update to the latest versions.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd cisa_csaf_ot nvd siemens_psirt NVD CVE.org MITRE

published 2021-09-14modified 2026-06-17

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references (8)

External citations — patches, advisories, analysis.

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