CVE-2020-10245Public exploitNetwork attack vector

Unauthenticated code execution via allocation-size integer overflow

Published Mar 26, 2020 · Updated Aug 4, 2024

Heap-based buffer overflow in the CODESYS V3 web server before 3.5.15.40 allows remote attackers to crash the runtime or execute code. CmpWebServerHandlerV3 accepts 0xffffffff as a communication-buffer size, and MemGCGetSize adds 0x5c with 32-bit wraparound before allocating a small heap buffer. A subsequent WEB_CLIENT_RUN_SERVICE message copies attacker-controlled data into that undersized buffer; the optional web server must be enabled, but no authentication or user interaction is required.

CVSS severity10.0
Critical
EPSS probability2.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in the CODESYS V3 web server before 3.5.15.40 allows remote attackers to crash the runtime or execute code. CmpWebServerHandlerV3 accepts 0xffffffff as a communication-buffer size, and MemGCGetSize adds 0x5c with 32-bit wraparound before allocating a small heap buffer. A subsequent WEB_CLIENT_RUN_SERVICE message copies attacker-controlled data into that undersized buffer; the optional web server must be enabled, but no authentication or user interaction is required.

The record

CVE
CVE-2020-10245
Published
Mar 26, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 26, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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

9.8NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
10.03S-Smart Software Solutions GmbHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
10.0NIST National Vulnerability DatabaseAV:N/AC:L/Au:N/C:C/I:C/A:C

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 exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1190Exploit Public-Facing Application

Public exploit references

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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