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CVE-2021-40368

25
FAUCET Score

CVE-2021-40368 is a Denial-of-Service vulnerability affecting numerous Siemens SIMATIC S7-400 and S7-410 CPU families. An unauthenticated attacker can exploit this by sending specially crafted packets to port 102/tcp, causing the affected device to crash and require a manual restart. This vulnerability carries a CVSS score of 7.5 (HIGH), indicating a significant risk due to its network-based attack vector, low attack complexity, and complete loss of availability. There is no confidentiality or integrity impact. Currently, there is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage regarding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 6.0.10CPE matchmatch criteria
cpe:2.3:o:siemens:simatic_s7-400h_v6_firmware:*:*:*:*:*:*:*:*
All Versions ImpactedCPE matchmatch criteria
cpe:2.3:o:siemens:simatic_s7-400_pn\/dp_v7_firmware:*:*:*:*:*:*:*:*
All Versions ImpactedCPE matchmatch criteria
cpe:2.3:o:siemens:simatic_s7-410_v8_firmware:*:*:*:*:*:*:*:*
< 10.1CPE matchmatch criteria
cpe:2.3:o:siemens:simatic_s7-410_v10_firmware:*:*:*:*:*:*:*:*

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
0.97%
Probability of exploitation in next 30 days
EPSS Percentile
58.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0097 is in the 33rd percentile among its peer group of 51,553 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

No media coverage found for this CVE.

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-557541.pdf
PatchVendor Advisory