CVE-2019-5166Public exploit

Code execution via unchecked DNS cache formatting

Published Mar 10, 2020 · Updated Aug 4, 2024

Stack buffer overflow in iocheckd in WAGO PFC200 Firmware 03.02.02(14) allows local users to execute code via a crafted XML cache file. The DNS value from globally writable /tmp/iocheckCache.xml is passed to sprintf into a 1,024-byte stack buffer without a length bound. Local file write access is required, and a BC_SaveParameter packet to the I/O-Check service triggers parsing and permits attacker-controlled code execution.

CVSS severity8.8
High
EPSS probability0.82%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack buffer overflow in iocheckd in WAGO PFC200 Firmware 03.02.02(14) allows local users to execute code via a crafted XML cache file. The DNS value from globally writable /tmp/iocheckCache.xml is passed to sprintf into a 1,024-byte stack buffer without a length bound. Local file write access is required, and a BC_SaveParameter packet to the I/O-Check service triggers parsing and permits attacker-controlled code execution.

The record

CVE
CVE-2019-5166
Published
Mar 10, 2020
Updated
Aug 4, 2024
Vendor
WAGO
Product
WAGO PFC200 Firmware
Classifications
CWE-120, CWE-787, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 10, 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?

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

  1. Affected versionversion=version 03.02.02(14)

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

WAGO · WAGO PFC200 Firmwareversion=version 03.02.02(14)

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.8Cisco TalosCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
6.8NIST NVDAV:L/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.

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No observations available

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

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CWE-787Out-of-bounds Write
T1068Exploitation for Privilege Escalation

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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