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CVE-2021-37185

25
FAUCET Score

CVE-2021-37185 describes a denial-of-service vulnerability affecting various Siemens SIMATIC S7-1200, S7-1500, and Drive Controller families, among other products. An unauthenticated attacker can exploit this by sending specially crafted packets to port 102/tcp, causing the PLC to crash and requiring a manual restart. This vulnerability has a CVSS score of 7.5 (High) due to its network attack vector, low attack complexity, and high impact on availability. While there is no known public exploit code or active exploitation, the vulnerability has garnered some community discussion and media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
< 2.9.4CPE matchmatch criteria
cpe:2.3:o:siemens:simatic_drive_controller_cpu_1504d_tf_firmware:*:*:*:*:*:*:*:*
< 2.9.4CPE matchmatch criteria
cpe:2.3:o:siemens:simatic_drive_controller_cpu_1507d_tf_firmware:*:*:*:*:*:*:*:*
All Versions ImpactedCPE matchmatch criteria
cpe:2.3:o:siemens:simatic_et_200sp_open_controller_cpu_1515sp_pc2_firmware:*:*:*:*:*:*:*:*
< 4.0CPE matchmatch criteria
cpe:2.3:o:siemens:simatic_s7-plcsim_advanced_firmware:*:*:*:*:*:*:*:*
4.0CPE matchmatch criteria
cpe:2.3:o:siemens:simatic_s7-plcsim_advanced_firmware:4.0:-:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
2.06%
Probability of exploitation in next 30 days
EPSS Percentile
79.3%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0206 is in the 64th percentile among its peer group of 51,551 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

cert-portal.siemens.com / productcert/pdf/ssa-838121.pdf
PatchVendor Advisory