HOMEVULNERABILITIESCVE-2020-12526
MEDIUM

CVE-2020-12526

CWE-20Published: May 13, 2021· Updated: Jun 17, 2026

5.3
CVSS v3.1

Official Description

TwinCAT OPC UA Server in versions up to 2.3.0.12 and IPC Diagnostics UA Server in versions up to 3.1.0.1 from Beckhoff Automation GmbH & Co. KG are vulnerable to denial of service attacks. The attacker needs to send several specifically crafted requests to the running OPC UA server. After some of these requests the OPC UA server is no longer responsive to any client. This is without effect to the real-time functionality of IPCs.

NVD Source

Technical Analysis

CVE-2020-12526 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityLow
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected Vendors & Products

beckhoff3 product(s)
ipc diagnostics ua servertf6100twincat opc ua server
Source: NVD CPE · 3 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://cert.vde.com/en-us/advisories/vde-2020-051
ADVISORYhttps://download.beckhoff.com/download/Document/product-security/Advisories/advisory-2021-001.pdf
ADVISORYhttps://cert.vde.com/en-us/advisories/vde-2020-051
ADVISORYhttps://download.beckhoff.com/download/Document/product-security/Advisories/advisory-2021-001.pdf

All References (4)

→
https://cert.vde.com/en-us/advisories/vde-2020-051Third Party Advisory
→
https://download.beckhoff.com/download/Document/product-security/Advisories/advisory-2021-001.pdfVendor Advisory
→
https://cert.vde.com/en-us/advisories/vde-2020-051Third Party Advisory
→
https://download.beckhoff.com/download/Document/product-security/Advisories/advisory-2021-001.pdfVendor Advisory

Quick Facts

CVE IDCVE-2020-12526
CVSS Score5.3 / 10
SeverityMEDIUM
WeaknessCWE-20
CISA KEVNo
Affected1 vendor(s)
PublishedMay 13, 2021

Related CVEs (CWE-20)

CVE-2011-3097
10.0
CVE-2012-2321
10.0
CVE-2011-3092
10.0
CVE-2011-3095
10.0
CVE-2012-2118
10.0
CVE-2010-5185
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2020-12526 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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