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NVD / CVE Program· CNA siemens

CVE-2021-37204: A vulnerability has been identified in SIMATIC Drive Controller family (All versions < V2.9.2), SIMATIC Drive Controller family (All version

Noroxi assessment

Priority: Monitor (action score 31/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 2.1% (FIRST EPSS); higher than 82.4% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • According to the record, no fixed version is available yet.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

A vulnerability has been identified in SIMATIC Drive Controller family (All versions < V2.9.2), SIMATIC Drive Controller family (All versions >= V2.9.2 < V2.9.4), SIMATIC ET 200SP Open Controller CPU 1515SP PC (incl. SIPLUS variants) (All versions), SIMATIC ET 200SP Open Controller CPU 1515SP PC2 (incl. SIPLUS variants) (All versions < V21.9), SIMATIC ET 200SP Open Controller CPU 1515SP PC2 (incl. SIPLUS variants) (All versions >= V21.9 < V21.9.4), SIMATIC ET 200SP Open Controller CPU 1515SP PC2 Ready4Linux (All versions), SIMATIC S7-1200 CPU family (incl. SIPLUS variants) (All versions < V4.5.0), SIMATIC S7-1200 CPU family (incl. SIPLUS variants) (All versions >= V4.5.0 < V4.5.2), SIMATIC S7-1500 CPU family (incl. related ET200 CPUs and SIPLUS variants) (All versions < V2.9.2), SIMATIC S7-1500 CPU family (incl. related ET200 CPUs and SIPLUS variants) (All versions >= V2.9.2 < V2.9.4), SIMATIC S7-1500 Software Controller (All versions < V21.9), SIMATIC S7-1500 Software Controller (All versions >= V21.9 < V21.9.4), SIMATIC S7-PLCSIM Advanced (All versions < V4.0), SIMATIC S7-PLCSIM Advanced (All versions >= V4.0 < V4.0 SP1), SIPLUS TIM 1531 IRC (All versions < V2.3.6), TIM 1531 IRC (All versions < V2.3.6). An unauthenticated attacker could cause a denial-of-service condition in a PLC when sending specially prepared packet over port 102/tcp. A restart of the affected device is needed to restore normal operations.

HighCVSS 7.5 · v3.1—No exploit No fix recorded
Published
Feb 9, 2022
Updated
Jun 17, 2026
EPSS
2.1% · 82th percentile

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 2.1%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · siemens
7.5
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-37204

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
siemenssimatic drive controller cpu 1504d tf firmware
siemenssimatic drive controller cpu 1504d tf
siemenssimatic drive controller cpu 1507d tf firmware
siemenssimatic drive controller cpu 1507d tf
siemenssimatic et 200sp open controller cpu 1515sp pc2 firmware
siemenssimatic et 200sp open controller cpu 1515sp pc2
siemenssimatic s7-plcsim advanced firmware
siemenssimatic s7-plcsim advanced
siemenstim 1531 irc firmware
siemenstim 1531 irc
siemenssimatic s7-1500 software controller
siemenssimatic s7-1200 cpu 1211c firmware

and 83 more

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • siemens simatic drive controller cpu 1504d tf firmwarebefore 2.9.4
  • siemens simatic drive controller cpu 1507d tf firmwarebefore 2.9.4
  • siemens simatic et 200sp open controller cpu 1515sp pc2 firmwareall versions
  • siemens simatic s7-1200 cpu 1211c firmware4.5.0 and later · before 4.5.2
  • siemens simatic s7-1200 cpu 1212c firmware4.5.0 and later · before 4.5.2
  • siemens simatic s7-1200 cpu 1212fc firmware4.5.0 and later · before 4.5.2
  • siemens simatic s7-1200 cpu 1214c firmware4.5.0 and later · before 4.5.2
  • siemens simatic s7-1200 cpu 1214fc firmware4.5.0 and later · before 4.5.2
  • siemens simatic s7-1200 cpu 1215c firmware4.5.0 and later · before 4.5.2
  • siemens simatic s7-1200 cpu 1215fc firmware4.5.0 and later · before 4.5.2
  • siemens simatic s7-1200 cpu 1217c firmware4.5.0 and later · before 4.5.2
  • siemens simatic s7-1500 cpu 1510sp firmware2.9.2 and later · before 2.9.4
  • siemens simatic s7-1500 cpu 1510sp-1 firmware2.9.2 and later · before 2.9.4
  • siemens simatic s7-1500 cpu 1511-1 firmware2.9.2 and later · before 2.9.4
  • siemens simatic s7-1500 cpu 1511c-1 firmware2.9.2 and later · before 2.9.4
  • siemens simatic s7-1500 cpu 1511f-1 firmware2.9.2 and later · before 2.9.4
  • siemens simatic s7-1500 cpu 1511t-1 firmware2.9.2 and later · before 2.9.4
  • siemens simatic s7-1500 cpu 1511tf-1 firmware2.9.2 and later · before 2.9.4
  • siemens simatic s7-1500 cpu 1512c-1 firmware2.9.2 and later · before 2.9.4
  • siemens simatic s7-1500 cpu 1512sp-1 firmware2.9.2 and later · before 2.9.4

Versions reported by the vendor

Affected version ranges reported by the assigning authority (siemens). Independent of NVD's CPE analysis and usually ahead of it.

  • Siemens SIMATIC Drive Controller family

    • All versions < V2.9.2, All versions >= V2.9.2 < V2.9.4affected

  • Siemens SIMATIC ET 200SP Open Controller CPU 1515SP PC (incl. SIPLUS variants)

    • All versionsaffected

  • Siemens SIMATIC ET 200SP Open Controller CPU 1515SP PC2 (incl. SIPLUS variants)

    • All versions < V21.9, All versions >= V21.9 < V21.9.4affected

  • Siemens SIMATIC ET 200SP Open Controller CPU 1515SP PC2 Ready4Linux

    • All versionsaffected

  • Siemens SIMATIC S7-1200 CPU family (incl. SIPLUS variants)

    • All versions < V4.5.0, All versions >= V4.5.0 < V4.5.2affected

  • Siemens SIMATIC S7-1500 CPU family (incl. related ET200 CPUs and SIPLUS variants)

    • All versions < V2.9.2, All versions >= V2.9.2 < V2.9.4affected

  • Siemens SIMATIC S7-1500 Software Controller

    • All versions < V21.9, All versions >= V21.9 < V21.9.4affected

  • Siemens SIMATIC S7-PLCSIM Advanced

    • All versions < V4.0, All versions >= V4.0 < V4.0 SP1affected

  • Siemens SIPLUS TIM 1531 IRC

    • All versions < V2.3.6affected

  • Siemens TIM 1531 IRC

    • All versions < V2.3.6affected

Same product

siemens: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-37185A vulnerability has been identified in SIMATIC Drive Controller family (All versions >= V2.9.2 < V2.9.4), SIMATIC ET 200SP Open Controller C
    31Monitor
  • CVE-2023-46156Affected devices improperly handle specially crafted packets sent to port 102/tcp.
    30Monitor
  • CVE-2021-37205A vulnerability has been identified in SIMATIC Drive Controller family (All versions >= V2.9.2 < V2.9.4), SIMATIC ET 200SP Open Controller C
    30Monitor

Published before and after this one in the same product

  • Later →CVE-2022-38773Jan 10, 2023 · Affected devices do not contain an Immutable Root of Trust in Hardware.
    27Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-672 · Operation on a Resource after Expiration or Release

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records