CVE-2021-27486Public exploit

Arbitrary code execution via PWD parsing underflow

Published Apr 12, 2021 · Updated Aug 3, 2024

Integer underflow in FATEK Automation WinProladder 3.30 and earlier allows remote attackers to execute arbitrary code via malicious PWD files. The PWD parser fails to validate attacker-supplied values before subtracting and writing to memory, producing an out-of-bounds write. Exploitation requires a user to open the crafted project file; code runs in the current process context.

CVSS severity7.8
High
EPSS probability0.98%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer underflow in FATEK Automation WinProladder 3.30 and earlier allows remote attackers to execute arbitrary code via malicious PWD files. The PWD parser fails to validate attacker-supplied values before subtracting and writing to memory, producing an out-of-bounds write. Exploitation requires a user to open the crafted project file; code runs in the current process context.

The record

CVE
CVE-2021-27486
Published
Apr 12, 2021
Updated
Aug 3, 2024
Vendor
FATEK Automation Corporation
Product
WinProladder
Classifications
CWE-191, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 12, 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?

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

  1. Affected versionversion=WinProladder Versions 3.30 and prior

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

FATEK Automation Corporation · WinProladderversion=WinProladder Versions 3.30 and prior

Published CVSS scores

6.8NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
7.8ICS-CERTCVSS:3.1/AV:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-191Integer Underflow (Wrap or Wraparound)
T1203Exploitation for Client Execution

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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