CVE-2023-50821

Persistent runtime denial via unchecked login input

Published Apr 9, 2024 · Updated Feb 26, 2025

Buffer overflow in Siemens SIMATIC WinCC products allows local users to persistently halt the SCADA runtime through the login dialog. The dialog copies attacker-controlled login input without checking its size, allowing an oversized value to corrupt runtime memory. Local access to the login dialog is required; successful exploitation persistently interrupts operator visualization and control runtime.

CVSS severity6.2
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in Siemens SIMATIC WinCC products allows local users to persistently halt the SCADA runtime through the login dialog. The dialog copies attacker-controlled login input without checking its size, allowing an oversized value to corrupt runtime memory. Local access to the login dialog is required; successful exploitation persistently interrupts operator visualization and control runtime.

The record

CVE
CVE-2023-50821
Published
Apr 9, 2024
Updated
Feb 26, 2025
Vendor
Siemens
Product
SIMATIC WinCC
Classifications
CWE-120, T1499
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 9, 2024CVE publishedPublication date reported by the CVE source.
  2. Feb 26, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=0 <V7.5 SP2 Update 16
  2. Affected versionversion=0 <V8.0 Update 5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Siemens · SIMATIC WinCCversion=0 <V7.5 SP2 Update 16; version=0 <V8.0 Update 5
Siemens · SIMATIC PCS 7version=0 <V9.1 SP2 UC04
Siemens · SIMATIC WinCC Runtime Professionalversion=0 <V17 Update 8; version=0 <V18 Update 4; version=0 <V19 Update 1

Published CVSS scores

6.2Siemens AGCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
6.9Siemens AGCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1499Endpoint Denial of Service

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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