{"cve":"CVE-2020-12526","nvd":{"published":"2021-05-13T14:15:17.457","modified":"2026-06-17T02:51:58.547","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","score":5.3},"cwes":["CWE-20"],"references":["https://cert.vde.com/en-us/advisories/vde-2020-051","https://download.beckhoff.com/download/Document/product-security/Advisories/advisory-2021-001.pdf","https://cert.vde.com/en-us/advisories/vde-2020-051","https://download.beckhoff.com/download/Document/product-security/Advisories/advisory-2021-001.pdf"],"products":["beckhoff:ipc_diagnostics_ua_server","beckhoff:tf6100","beckhoff:twincat_opc_ua_server"],"source":"nvd","synced_at":"2026-10-19T21:18:09.669877188+00:00"},"epss":{"cve":"CVE-2020-12526","score":0.00955,"percentile":0.61404,"date":"2026-11-01"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}