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NVD / CVE Program· CNA mitre

CVE-2021-30186: CODESYS V2 runtime system SP before 2.4.7.55 has a Heap-based Buffer Overflow.

Noroxi assessment

Priority: Monitor (action score 32/100)

  • 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: 7.7% (FIRST EPSS); higher than 94.6% 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 the record, no fixed version is available yet.
  • Mentioned 2 times 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

HighCVSS 7.5 · v3.1—No exploit No fix recorded
Published
May 25, 2021
Updated
Jun 16, 2026
EPSS
7.7% · 94th percentile

Report tools

JSON

Action score

32

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
2 / 30 · 7.7%

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-2021-30186

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
codesysplcwinnt
codesysruntime toolkit
wago750-893 firmware
wago750-893
wago750-891 firmware
wago750-891
wago750-890 firmware
wago750-890
wago750-889 firmware
wago750-889
wago750-885 firmware
wago750-885

and 44 more

Affected versions

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

  • codesys plcwinntbefore 2.4.7.55
  • codesys runtime toolkitbefore 2.4.7.55
  • wago 750-8202 firmwarebefore 03.06.19_\(18\)
  • wago 750-8203 firmwarebefore 03.06.19_\(18\)
  • wago 750-8204 firmwarebefore 03.06.19_\(18\)
  • wago 750-8206 firmwarebefore 03.06.19_\(18\)
  • wago 750-8207 firmwarebefore 03.06.19_\(18\)
  • wago 750-8208 firmwarebefore 03.06.19_\(18\)
  • wago 750-8210 firmwarebefore 03.06.19_\(18\)
  • wago 750-8211 firmwarebefore 03.06.19_\(18\)
  • wago 750-8212 firmwarebefore 03.06.19_\(18\)
  • wago 750-8213 firmwarebefore 03.06.19_\(18\)
  • wago 750-8214 firmwarebefore 03.06.19_\(18\)
  • wago 750-8216 firmwarebefore 03.06.19_\(18\)
  • wago 750-8217 firmwarebefore 03.06.19_\(18\)
  • wago 750-823 firmwarebefore fw08
  • wago 750-829 firmwarebefore fw15
  • wago 750-831 firmwarebefore fw15
  • wago 750-832 firmwarebefore fw08
  • wago 750-852 firmwarebefore fw15

Same product

codesys: all records

Other highest-scoring records for the same primary product.

  • CVE-2022-31806Insecure default settings in CODESYS Runtime Toolkit 32 bit full and CODESYS PLCWinNT
    39Monitor
  • CVE-2022-32143CODESYS runtime system prone to directory acces
    35Monitor
  • CVE-2022-32138CODESYS runtime system prone to denial of service due to Unexpected Sign Extension
    35Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2019-19789Dec 20, 2019 · 3S-Smart CODESYS SP Realtime NT before V2.3.7.28, CODESYS Runtime Toolkit 32 bit full before V2.4.7.54, and CODESYS PLCWinNT before V2.4.7.5
    26Monitor
  • Later →CVE-2021-30195May 25, 2021 · CODESYS V2 runtime system before 2.4.7.55 has Improper Input Validation.
    32Monitor
  • Later →CVE-2021-34593Oct 26, 2021 · CODESYS V2 runtime: unauthenticated invalid requests may result in denial-of-service
    31Monitor

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-787 · Out-of-bounds Write

CVSS vector

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

nvd-primary

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

Show all references (1 more)

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

All records