COMMUNITY FINANCIAL SYSTEM, INC.

Evaluation of Disclosure Controls and Procedures

The Company maintains disclosure controls and procedures, as defined in Rule 13a -15(e) and 15d – 15(e) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), designed to: (i) record, process, summarize, and report within the time periods specified in the SEC’s rules and forms, and (ii) accumulate and communicate to management, including the principal executive and principal financial officers, as appropriate, to allow timely decisions regarding disclosure. Based on evaluation of the Company’s disclosure controls and procedures, with the participation of the Chief Executive Officer (“CEO”) and the Chief Financial Officer (“CFO”), the CEO and CFO have concluded that, as of the end of the period covered by this Annual Report on Form 10-K, these disclosure controls and procedures were effective as of December 31, 2025.

Management’s Annual Report on Internal Control over Financial Reporting

Management’s annual report on internal control over financial reporting is included under the heading “Report on Internal Control Over Financial Reporting” at Item 8 of this Annual Report on Form 10-K.

Report of the Registered Public Accounting Firm

The report of the Company’s registered public accounting firm is included under the heading “Report of the Independent Registered Public Accounting Firm” at Item 8 of this Annual Report on Form 10-K.

Changes in Internal Control over Financial Reporting

The Company continually assesses the adequacy of its internal control over financial reporting and enhances its controls in response to internal control assessments, and internal and external audit and regulatory recommendations. No change in internal control over financial reporting during the quarter ended December 31, 2025 has materially affected, or is reasonably likely to materially affect, the Company’s internal control over financial reporting.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate due to changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.