INTELLECTUAL PROPERTY SECURITY AGREEMENT

Exhibit 10.28

INTELLECTUAL PROPERTY SECURITY AGREEMENT

INTELLECTUAL PROPERTY SECURITY AGREEMENT dated as of October 18, 2012 by and among SILICON VALLEY BANK, a California corporation with a loan production office located at 14185 Dallas Parkway, Suite 760, Dallas TX 75254 (“Bank”), MAVENIR SYSTEMS, INC., a Delaware corporation (“Mavenir”), MAVENIR HOLDINGS, INC., a Delaware corporation, (“Holdings” and together with Mavenir, individually and collectively, jointly and severally, the “Grantor”) each with offices located at 1651 North Glenville Drive, Suite 216, Richardson, Texas 75081.

RECITALS

A. Bank has agreed to make certain advances of money and to extend certain financial accommodation to Grantor (the “Loans”) in the amounts and manner set forth in (i) that certain Senior Loan and Security Agreement by and among Bank and Grantor, dated as of October 18, 2012 (the “Senior Loan Agreement”) and (ii) that certain Subordinated Loan and Security Agreement by and among Bank and Grantor, dated as of October 18, 2012 (the “Subordinated Loan Agreement” and together with the Senior Loan Agreement, each as the same may be amended, modified or supplemented from time to time, collectively the “Loan Agreements”; capitalized terms used herein are used as defined in the Loan Agreement). Bank is willing to make the Loans to Grantor, but only upon the condition, among others, that Grantor shall grant to Bank a security interest in certain Copyrights, Trademarks, Patents, and Mask Works (as each term is described below) to secure the obligations of Grantor under the Loan Agreements.

B. Pursuant to the terms of the Loan Agreements, Grantor has granted to Bank a security interest in all of Grantor’s right, title and interest, whether presently existing or hereafter acquired, in, to and under all of the Collateral.

C. Bank’s security interest in the assets of Grantor securing the Obligations of Grantor to Bank under the Subordinated Loan Agreement shall be junior and subordinate to Bank’s security interest in the assets of Grantor securing the Obligations of Grantor under the Senior Loan Agreement.

NOW, THEREFORE, for good and valuable consideration, receipt of which is hereby acknowledged, and intending to be legally bound, as collateral security for the prompt and complete payment when due of its obligations under the Loan Agreements, Grantor hereby represents, warrants, covenants and agrees as follows:

AGREEMENT

To secure its obligations under the Loan Agreements, Grantor grants and pledges to Bank a security interest in all of Grantor’s right, title and interest in, to and under its intellectual property (all of which shall collectively be called the “Intellectual Property Collateral”), including, without limitation, the following:

1. Any and all copyright rights, copyright applications, copyright registrations and like protections in each work or authorship and derivative work thereof, whether published or unpublished and whether or not the same also constitutes a trade secret, now or hereafter existing, created, acquired or held, including without limitation those set forth on Exhibit A attached hereto (collectively, the “Copyrights”);

2. Any and all trade secrets, and any and all intellectual property rights in computer software and computer software products now or hereafter existing, created, acquired or held;

3. Any and all design rights that may be available to Grantor now or hereafter existing, created, acquired or held;

4. All patents, patent applications and like protections including, without limitation, improvements, divisions, continuations, renewals, reissues, extensions and continuations-in-part of the same, including without limitation the patents and patent applications set forth on Exhibit B attached hereto (collectively, the “Patents”);

5. Any trademark and servicemark rights, whether registered or not, applications to register and registrations of the same and like protections, and the entire goodwill of the business of Grantor connected with and symbolized by such trademarks, including without limitation those set forth on Exhibit C attached hereto (collectively, the “Trademarks”);

6. All mask works or similar rights available for the protection of semiconductor chips, now owned or hereafter acquired, including, without limitation those set forth on Exhibit D attached hereto (collectively, the “Mask Works”);

7. Any and all claims for damages by way of past, present and future infringements of any of the rights included above, with the right, but not the obligation, to sue for and collect such damages for said use or infringement of the intellectual property rights identified above;

8. All licenses or other rights to use any of the Copyrights, Patents, Trademarks, or Mask Works and all license fees and royalties arising from such use to the extent permitted by such license or rights;

9. All amendments, extensions, renewals and extensions of any of the Copyrights, Trademarks, Patents, or Mask Works; and

10. All proceeds and products of the foregoing, including without limitation all payments under insurance or any indemnity or warranty payable in respect of any of the foregoing.

Notwithstanding the foregoing, the security interest shall not apply to any Excluded Property (as defined in the Loan Agreement).

This security interest is granted in conjunction with the security interest granted to Bank under the Loan Agreements. The rights and remedies of Bank with respect to the security interest granted hereby are in addition to those set forth in the Loan Agreements and the other Loan Documents, and those which are now or hereafter available to Bank as a matter of law or equity. Each right, power and remedy of Bank provided for herein or in the Loan Agreement or any of the Loan Documents, or now or hereafter existing at law or in equity shall be cumulative and concurrent and shall be in addition to every right, power or remedy provided for herein and the exercise by Bank of any one or more of the rights, powers or remedies provided for in this Intellectual Property Security Agreement, the Loan Agreements or any of the other Loan Documents, or now or hereafter existing at law or in equity, shall not preclude the simultaneous or later exercise by any person, including Bank, of any or all other rights, powers or remedies.

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[Signature page follows.]

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IN WITNESS WHEREOF, the parties have caused this Intellectual Property Security Agreement to be executed as a sealed instrument under the laws of the State of New York, as of the first date written above.

[Signature Page to IP Security Agreement]

[Signature Page to IP Security Agreement]

EXHIBIT A

Copyrights

EXHIBIT B

US Patents

Foreign Patents

EXHIBIT C

Trademarks

EXHIBIT D

Mask Works

None