A vulnerability has been identified in SIMATIC CP 1543-1 (incl.

published 2021-09-14 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-20393

cvss: 6.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 16%
public exploits: 0; none known

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.

Patch / fix

fixed in 2 links 1

siemens simatic_cp_1543-1_firmware 3.0
siemens simatic_cp_1545-1_firmware 1.1

cert-portal.siemens.com/productcert/pdf/ssa-535997.pdf advisory

Vendor advisories

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

cisa ICSA-21-257-06 updated 2022-06-14 cvss 6.5

Siemens SIMATIC CP (Update A)

Siemens SIMATIC CP 1543-1 (incl. SIPLUS variants) <V3.0
affected: fixed in V3.0 support.industry.siemens.com
Siemens SIMATIC CP 1545-1 <V1.1
affected: fixed in V1.1 support.industry.siemens.com

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

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	6.5	CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD	2.0	3.3	AV:A/AC:L/Au:N/C:P/I:N/A:N

Affected products

Siemens SIMATIC CP 1543-1 (incl. SIPLUS variants)
Siemens SIMATIC CP 1545-1

Classification

Weakness

CWE-312 Cleartext Storage of Sensitive Information

References

cert-portal.siemens.com /productcert/pdf/ssa-535997.pdf
patch, vendor-advisory

Sources

CVE List CVE-2021-33716
NVD CVE-2021-33716

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