CVE-2021-34586
CODESYS V2 web server: crafted requests could trigger a null pointer dereference (DoS)
HIGH
7.5
CVSS Score
Published: October 26, 2021 at 09:55 AM UTC
Updated: June 17, 2026 at 03:56 AM UTC
55 products affected across 2 vendors750-8202 Firmware750-862 Firmware750-823 Firmware
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Severity
HIGH7.5
Exploit prediction
EPSS 14%
Description
In the CODESYS V2 web server prior to V1.1.9.22 crafted web server requests may cause a Null pointer dereference in the CODESYS web server and may result in a denial-of-service condition.
Affected
Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.
Affected range stops below 1.1.9.22, so it looks safe — our inference, not a vendor statement
Affected range stops below V1.1.9.22, 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)
v < fw20
Affected range stops below fw20, so it looks safe — our inference, not a vendor statement
wago-750-8211 (same device)
v < fw20
Affected range stops below fw20, so it looks safe — our inference, not a vendor statement
wago-750-8212 (same device)
Remediation
No guide yetNo remediation guidance has been written for this CVE yet. What the record does show:
References (2)
x_refsource_CONFIRMVendor Advisory
Source: [email protected]
https://customers.codesys.com/index.php?eID=dumpFile&t=f&f=16876&token=a3f1d937f95e7034879f4f2ea8e5a99b168256a7&download=x_refsource_MISCExploitThird Party Advisory
Source: [email protected]
https://www.tenable.com/security/research/tra-2021-47CVSS
7.5HIGHCERTVDE
- Attack Vector
- NETWORK
- Complexity
- LOW
- Privileges
- NONE
- User Interaction
- NONE
- Scope
- UNCHANGED
- Confidentiality
- NONE
- Integrity
- NONE
- Availability
- HIGH
Vector?
Quick Info
StatusANALYZED
CWE
CWE-476
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