CVE-2021-34595

CODESYS V2 runtime: out-of-bounds read or write access may result in denial-of-service

HIGH
8.1
CVSS Score
Published: October 26, 2021 at 09:55 AM UTC
Updated: June 17, 2026 at 03:56 AM UTC
49 products affected across 2 vendorsRuntime Toolkit750-880750-881

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Severity
HIGH8.1
Exploit prediction
EPSS 0.9%

Description

A crafted request with invalid offsets may cause an out-of-bounds read or write access in CODESYS V2 Runtime Toolkit 32 Bit full and PLCWinNT prior to versions V2.4.7.56, resulting in a denial-of-service condition or local memory overwrite.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.1.9.22PLCWinNT ≤ v < V2.4.7.56Runtime Toolkit 32 bit full ≤ v < V2.4.7.56PLCWinNTRuntime Toolkit 32 bit full
Affected range stops below 1.1.9.22, so it looks safe — our inference, not a vendor statement
Affected range stops below V2.4.7.56, so it looks safe — our inference, not a vendor statement
v < 2.4.7.56
Affected range stops below 2.4.7.56, so it looks safe — our inference, not a vendor statement
v < 2.4.7.56
Affected range stops below 2.4.7.56, so it looks safe — our inference, not a vendor statement
v < fw20
Affected range stops below fw20, so it looks safe — our inference, not a vendor statement
wago-750-8202 (same device)
v < fw20
Affected range stops below fw20, so it looks safe — our inference, not a vendor statement
wago-750-8203 (same device)
v < fw20
Affected range stops below fw20, so it looks safe — our inference, not a vendor statement
wago-750-8204 (same device)
v < fw20
Affected range stops below fw20, so it looks safe — our inference, not a vendor statement
wago-750-8206 (same device)
v < fw20
Affected range stops below fw20, so it looks safe — our inference, not a vendor statement
wago-750-8207 (same device)
v < fw20
Affected range stops below fw20, so it looks safe — our inference, not a vendor statement
wago-750-8208 (same device)
v < fw20
Affected range stops below fw20, so it looks safe — our inference, not a vendor statement
wago-750-8210 (same device)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

CVSS

8.1HIGHCERTVDE
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-823CWE-119

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