CVE-2021-30193Network attack vector

Unauthenticated code execution via out-of-bounds memory write

Published May 25, 2021 · Updated Aug 3, 2024

Out-of-bounds write in CODESYS V2 Web-Server before 1.1.9.20 allows remote attackers to execute code or crash the Control runtime. A crafted web server request causes the Web-Server to write attacker-controlled data beyond a memory boundary in the CODESYS Control runtime. No authentication or user interaction is required; successful exploitation permits arbitrary runtime memory modification, while failure can terminate the runtime.

CVSS severity10.0
Critical
EPSS probability1.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in CODESYS V2 Web-Server before 1.1.9.20 allows remote attackers to execute code or crash the Control runtime. A crafted web server request causes the Web-Server to write attacker-controlled data beyond a memory boundary in the CODESYS Control runtime. No authentication or user interaction is required; successful exploitation permits arbitrary runtime memory modification, while failure can terminate the runtime.

The record

CVE
CVE-2021-30193
Published
May 25, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T0819
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 25, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

10.0CODESYS GmbHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T0819Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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