15 November 2023

Corero Network Security plc

("Corero", or "the Company")

Director Subscription, Grant of Options and Total Voting Rights

Corero Network Security plc (AIM: CNS), is pleased to announce that, further to the announcement on 13 November 2023, Carl Herberger, CEO Designate of the Company has entered into a subscription agreement to acquire 1,344,497 new Corero shares at a price of 9.0 pence per share.

In addition to this, Carl has been granted a matching share option award of 4,033,492 options over new ordinary shares with an exercise price of 9.0 pence, and as a part of Carl's overall CEO compensation, he has also been granted 7,500,000 options with an exercise price of 9.0 pence (together, the "Options"). The Options have a three-year vesting period, vesting one third on the first anniversary of grant, one third on the second anniversary of grant and one third on the third anniversary of grant. Shares acquired on the exercise of an option may not be sold until the expiry of the second anniversary following the date of option grant.

Following the subscription, Carl Herberger's holding in the Company will be 1,344,497 shares, representing 0.27% of the Company's enlarged issued share capital.

Application has been made for the 1,344,497 new Ordinary Shares to be admitted to trading on AIM ("Admission") and it is expected that Admission will become effective on 20 November 2023.

Following Admission, the total issued share capital of the Company with voting rights will be 501,528,468 Ordinary Shares. This figure may be used by shareholders in the Company as the denominator for the calculations by which they will determine if they are required to notify their interest in, or a change to their interest in, the share capital of the Company under the FCA's Disclosure Guidance and Transparency Rules.

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About Corero Network Security

Corero Network Security plc is a global leader in real-time, high-performance, automatic DDoS cyber defense solutions. Both Service and Hosting providers, alongside digital enterprises across the globe rely on Corero's award winning cybersecurity technology to eliminate the threat of Distributed Denial of Service (DDoS) to their digital environment through automatic attack detection and mitigation, coupled with network visibility, analytics and reporting.

Corero's industry leading SmartWall and SecureWatch technology provides scalable protection capabilities against external DDoS attackers and internal DDoS botnets in the most complex edge and subscriber environments, while enabling a more cost-effective economic model than previously available. Corero's key operational centers located in Marlborough, Massachusetts, USA and Edinburgh, UK, with the Company's headquarters in London, UK. The Company is listed on the London Stock Exchange's AIM market under the ticker CNS. For more information, visit www.corero.com.

This announcement, including the notification below, is made in accordance with the requirements of the EU Market Abuse Regulation.

Notification of a Transaction pursuant to Article 19(1) of Regulation (EU) No. 596/2014