CVE-2021-25674

Application crash via crafted-file NULL pointer dereference

Published Mar 15, 2021 · Updated Aug 3, 2024

NULL pointer dereference in Siemens SIMATIC S7-PLCSIM V5.4 allows local users to crash the application by opening a crafted file. The file-opening path dereferences a NULL pointer while processing the crafted input, causing unexpected termination. Local access and a crafted file are required, and restoring the simulation service requires restarting the application.

CVSS severity5.5
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in Siemens SIMATIC S7-PLCSIM V5.4 allows local users to crash the application by opening a crafted file. The file-opening path dereferences a NULL pointer while processing the crafted input, causing unexpected termination. Local access and a crafted file are required, and restoring the simulation service requires restarting the application.

The record

CVE
CVE-2021-25674
Published
Mar 15, 2021
Updated
Aug 3, 2024
Vendor
Siemens
Product
SIMATIC S7-PLCSIM
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 15, 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?

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  1. Affected versionversion=All versions

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Siemens · SIMATIC S7-PLCSIMversion=All versions

Published CVSS scores

2.1NIST NVDAV:L/AC:L/Au:N/C:N/I:N/A:P
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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.

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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 exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

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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