Germany’s telecommunications networks carry the country’s calls, data, and critical services, and the five CISOs below protect some of its biggest carriers and fastest-growing broadband providers. Several have spent most of their careers inside a single company. One has worked at Deutsche Telekom since 1997, leading technical security for nearly two decades before becoming Group CISO. Another has spent almost 28 years at Vodafone, moving from SAP and Oracle rollouts into cyber leadership. Others built their careers in healthcare IT, consulting, and penetration testing before taking on the networks that keep Germany connected.
Stefan Pütz – Group CISO & SVP Cyber & Digital Security, Deutsche Telekom
Dr. Stefan Pütz joined Deutsche Telekom in 1997 and spent 19 years as head of technical security. He moved to T-Systems in 2017 as VP of network and infrastructure security, then led network and IT security at Deutsche Telekom Security and became SVP of technical security and telco core services in 2021. Pütz has served as CISO of Deutsche Telekom Group since December 2022, alongside senior vice president roles at Deutsche Telekom Security, and in September 2026 took on responsibility for cyber and digital security. In 2024 he co-moderated a CISO workshop at the SEKOP security conference.
Oliver Sievers – CISO, Vodafone Shared Service Center & Data Center
Oliver Sievers has spent nearly 28 years at Vodafone. He began as technical delivery and deployment manager for Vodafone Germany and the Netherlands in a global SAP rollout, then led IT delivery for an Oracle Hyperion planning rollout across 19 markets and its transition to an in-house shared service center. In 2016 he became head of cyber security for the Vodafone Shared Service Centre, leading a team of 19 across the UK, Hungary, Romania, India, and Egypt, introducing a cyber security baseline and risk management framework, and supporting GDPR compliance and ISO 27001 certification. Sievers has served as CISO for Vodafone Technology IT operations and the shared service center since April 2021, covering seven locations and 25,000 employees, and represents cyber security in works council negotiations on program rollouts.
Borris Hoffmeister – CISO, Deutsche GigaNetz
Borris Hoffmeister led a multimedia team at Gebr. Heinemann before moving into healthcare IT at Gesundheitsholding Lüneburg, where he led IT quality and risk management for a team of 15 and built an ISMS as IT security officer. At ISG Intermed Service he served as deputy IT head, leading 52 IT staff and acting as IT security officer for more than 20 laboratories. After a period as an independent IT consultant and two years as senior manager of information security at Otto Group, he joined Deutsche GigaNetz in 2023 as IT continuity and security manager and AI officer. Hoffmeister became CISO in June 2026 and has led the communications topic working group of the BSI’s UP KRITIS critical infrastructure partnership since 2025.
Jochen Klein – Head of Information Security, 1&1 Telecommunication
Jochen Klein started as an IT service advisor at 1&1 Internet in Montabaur before moving into security consulting. At softScheck he worked on penetration testing, threat modeling, and source code analysis, and developed an application security framework based on ISO 27034. He went on to advise on information risk at CARMAO and plenum. As CISO of CompuGroup Medical from 2020 to 2024, he implemented group information security and business continuity management, established the security operations center, and drove the company’s product security program. Klein returned to 1&1 in February 2024 as head of information security at 1&1 Telecommunication.
Wolfgang Siebert – CISO & Compliance Officer, Deutsche Telekom Technik
Wolfgang Siebert has spent nearly three decades at Deutsche Telekom. He began as senior manager for data center strategy in Darmstadt and led application management for products and innovation, before joining Deutsche Telekom Technik in 2012. There he led data system and service operations, network evolution, and security technology as vice president. Siebert has served as CISO and compliance officer of Deutsche Telekom Technik since February 2019.
Securing the Backbone
These five CISOs show the depth of experience behind Germany’s telecommunications security. Pütz, Siebert, and Sievers have each spent decades inside the carriers they now protect, while Hoffmeister and Klein brought healthcare, consulting, and offensive security experience into the sector. Together they defend the networks that keep German households, businesses, and critical services connected.
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John Kevin Hao is a news and feature writer covering cybersecurity, technology, and business targeted for professional audiences.