CVE-2023-3663Network attack vector

Code execution via tampered HTTP notification links

Published Aug 3, 2023 · Updated Feb 27, 2025

Message-integrity failure in CODESYS Development System 3.5.11.20 through 3.5.19.19 allows man-in-the-middle attackers to execute code. Its Notification Center accepts messages from the CODESYS notification server over unencrypted HTTP without checking whether they were altered in transit. Exploitation requires control of the network path and a user click on an injected Learn More link, after which attacker-supplied code runs in the user's context.

CVSS severity8.8
High
EPSS probability1.02%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Message-integrity failure in CODESYS Development System 3.5.11.20 through 3.5.19.19 allows man-in-the-middle attackers to execute code. Its Notification Center accepts messages from the CODESYS notification server over unencrypted HTTP without checking whether they were altered in transit. Exploitation requires control of the network path and a user click on an injected Learn More link, after which attacker-supplied code runs in the user's context.

The record

CVE
CVE-2023-3663
Published
Aug 3, 2023
Updated
Feb 27, 2025
Vendor
CODESYS GmbH
Product
CODESYS Development System
Classifications
CWE-940, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 3, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 27, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3.5.11.20 <3.5.19.20

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

CODESYS GmbH · CODESYS Development Systemversion=3.5.11.20 <3.5.19.20

Published CVSS scores

8.8CERT VDECVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-940Improper Verification of Source of a Communication Channel
T1204.001User Execution: Malicious Link

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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