EX-32.1 4 rmbs-ex32_1.htm EX-32.1

Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

I, Luc Seraphin, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that the Quarterly Report on Form 10-Q of Rambus Inc. for the quarter ended September 30, 2025, fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended, and that information contained in such Quarterly Report on Form 10-Q fairly presents, in all material respects, the financial condition and results of operations of Rambus Inc.

Date: October 28, 2025

| By: | /s/ Luc Seraphin
| Name: | Luc Seraphin
| Title: | Chief Executive Officer (Principal Executive Officer)