CVE & CISA-KEV Catalog

CVE-2021-34593

HIGHEPSS 84th pctl
7.5
CVSS v3
NVD

Description

In CODESYS V2 Runtime Toolkit 32 Bit full and PLCWinNT prior to versions V2.4.7.56 unauthenticated crafted invalid requests may result in several denial-of-service conditions. Running PLC programs may be stopped, memory may be leaked, or further communication clients may be blocked from accessing the PLC.

CWE-755

How to fix

Remediation Available
750-8202 firmwareNVD
Affected:< fw20Fixed in:fw20CVE-2021-34593derived from NVD
750-8203 firmwareNVD
Affected:< fw20Fixed in:fw20CVE-2021-34593derived from NVD
750-8204 firmwareNVD
Affected:< fw20Fixed in:fw20CVE-2021-34593derived from NVD
750-8206 firmwareNVD
Affected:< fw20Fixed in:fw20CVE-2021-34593derived from NVD
750-8207 firmwareNVD
Affected:< fw20Fixed in:fw20CVE-2021-34593derived from NVD
750-8208 firmwareNVD
Affected:< fw20Fixed in:fw20CVE-2021-34593derived from NVD
750-8210 firmwareNVD
Affected:< fw20Fixed in:fw20CVE-2021-34593derived from NVD
750-8211 firmwareNVD
Affected:< fw20Fixed in:fw20CVE-2021-34593derived from NVD
750-8212 firmwareNVD
Affected:< fw20Fixed in:fw20CVE-2021-34593derived from NVD
750-8213 firmwareNVD
Affected:< fw20Fixed in:fw20CVE-2021-34593derived from NVD
750-8214 firmwareNVD
Affected:< fw20Fixed in:fw20CVE-2021-34593derived from NVD
750-8216 firmwareNVD
Affected:< fw20Fixed in:fw20CVE-2021-34593derived from NVD
750-8217 firmwareNVD
Affected:< fw20Fixed in:fw20CVE-2021-34593derived from NVD
plcwinntNVD
Affected:< 2.4.7.56Fixed in:2.4.7.56CVE-2021-34593derived from NVD
runtime toolkitNVD
Affected:< 2.4.7.56Fixed in:2.4.7.56CVE-2021-34593derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityNone
IntegrityNone
AvailabilityHigh

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

Exploit Intelligence

2.65%probability of exploitation in 30 days
84thpercentile

Elevated risk: more likely to be exploited than 84% of all known CVEs.

References

Vendor Advisory1
Third-Party Advisory1
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-08-15.