CVE-2021-34585

mediumpriority · track · 20EPSS 0.009 · 59 %ileDEEUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.90% (59th) EPSS
CVSS 5 · medium
Is it mine?
83 products
Check your exposure
Who says so?
4 sources
cnnvd · enisa_euvd · nvd · phoenix_contact_psirt

EPSS · scored 2026-10-23

In the CODESYS V2 web server prior to V1.1.9.22 crafted web server requests can trigger a parser error. Since the parser result is not checked under all conditions, a pointer dereference with an invalid address can occur. This leads to a denial of service situation.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

  • Fixedphoenix_contact_psirt

    UPDATE A: fixed Firmware versions for 750-890/0xx-xxx, 750-891 and 750-893 We recommend all effected users with CODESYS 2.3 Runtime PLCs to update to the firmware version listed below. Series Ethernet Controller | Article Number | Fixed Firmware Versions | Available | |-------------------------|--------------------------|---------------------------| | 750-823 | >=FW10 | January 2022 | | 750-829 | >=FW17 | After BACnet certification | | 750-831/000-00x | >=FW17 | After BACnet certification | | 750-832/000-00x | >=FW10 | After BACnet certification | | 750-852 | >=FW17 | Q1 2022 | | 750-862 | >=FW10 | January 2022 | | 750-880/0xx-xxx | >=FW17 | Q1 2022 | | 750-881 | >=FW17 | Q1 2022 | | 750-882 | >=FW17 | Q1 2022 | | 750-885/0xx-xxx | >=FW17 | Q1 2022 | | 750-889 | >=FW17 | Q1 2022 | | 750-890/0xx-xxx | >=FW10 | January 2022 | | 750-891 | >=FW10 | January 2022 | | 750-893 | >=FW10 | January 2022 | PFC200 Controller | Article Number | Affected Firmware Versions | Approx. Available | |-------------------------|----------------------------|--------------------| | 750-8202/xxx-xxx | >=FW20 | January 2022 | | 750-8203/xxx-xxx | >=FW20 | January 2022 | | 750-8204/xxx-xxx | >=FW20 | January 2022 | | 750-8206/xxx-xxx | >=FW20 | January 2022 | | 750-8207/xxx-xxx | >=FW20 | January 2022 | | 750-8208/xxx-xxx | >=FW20 | January 2022 | | 750-8210/xxx-xxx | >=FW20 | January 2022 | | 750-8211/xxx-xxx | >=FW20 | January 2022 | | 750-8212/xxx-xxx | >=FW20 | January 2022 | | 750-8213/xxx-xxx | >=FW20 | January 2022 | | 750-8214/xxx-xxx | >=FW20 | January 2022 | | 750-8216/xxx-xxx | >=FW20 | January 2022 | | 750-8217/xxx-xxx | >=FW20 | January 2022 |

  • Mitigationphoenix_contact_psirt

    1. Use general security best practices to protect systems from local and network attacks. 2. Do not allow direct access to the device from untrusted networks. 3. Update to the latest firmware according to the table in chapter solutions. 4. Disable the CODESYS 2.3 WebVisualisation and CODESYS 2.3 port 2455. For further impact information and risk mitigation, please refer to the official CODESYS Advisory Website at https://www.codesys.com/security/security-reports.html

02

cvss

Technical severity, 0–10. One row per scoring source.

7.5
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 4.3–7.5

v2.05mediumAV:N/AC:L/Au:N/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 10 · impact 2.9
v2.04.3mediumAV:N/AC:L/Au:N/C:N/I:N/A:P/E:Usecondary · CVSS-BT (t0sche)
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · NVD / NIST USexploitability 3.9 · impact 3.6
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · ENISA EU
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · info@cert.vde.comexploitability 3.9 · impact 3.6
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · Phoenix Contact PSIRT DE
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-252USCWE-252US
04

affected products (83)

Products and version ranges known to be affected.

showing 20 of 83
05

advisories (1)

Vendor and ecosystem advisories describing this.

  • VDE-2021-056WAGO: Multiple Vulnerabilities in CODESYS Runtime 2.3 and WebVisualisation2021-11-16csaf · phoenix_contact_psirtDE

    Multiple vulnerabilities were reported in CODESYS 2.3 Runtime. The CODESYS 2.3 Runtime is an essential component in several WAGO PLCs. All vulnerable PLCs are listed in chapter 'Affected Products'. https://www.codesys.com/security/security-reports.html

06

also known as (3)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

cnnvdenisa_euvdnvdphoenix_contact_psirtNVDCVE.orgMITRE
published 2021-10-26modified 2026-06-17
08

references (7)

External citations — patches, advisories, analysis.

scry

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