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EXHIBIT 5.0     OPINION OF MULDOON MURPHY & AGUGGIA LLP



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                   [MULDOON MURPHY & AGUGGIA LLP LETTERHEAD]




                                 March 27, 2007



Board of Directors
CNB Financial Corp.
33 Waldo Street
Worcester, Massachusetts  01608-0830


         Re:      CNB Financial Corp. Amended and Restated Stock Option Plan

Members of the Board of Directors:

         We have been requested by CNB Financial Corp., a Massachusetts
corporation (the "Company"), to issue a legal opinion in connection with the
registration (the "Registration") of 398,400 shares of the Company's Common
Stock, par value $1.00 per share (the "Shares"). The Registration of the Shares
is being effected on a Form S-8.

         We have made such legal and factual examinations and inquiries as we
deemed advisable for the purpose of rendering this opinion. In our examination,
we have assumed and have not verified (i) the genuineness of all signatures,
(ii) the authenticity of all documents submitted to us as originals, (iii) the
conformity to the originals of all documents supplied to us as copies, and (iv)
the accuracy and completeness of all corporate records and documents and of all
certificates and statements of fact, in each case given or made available to us
by the Company.

         Based on the foregoing and limited in all respects to Massachusetts
law, it is our opinion that the shares reserved under the plan have been duly
authorized and, upon payment for and issuance of the shares in the manner
described in the plan, will be legally issued, fully paid and nonassessable.

         This opinion is rendered to you solely for your benefit in connection
with the issuance of the Shares as described above. This opinion should not be
quoted in whole or in part, or otherwise referred to or furnished to any
governmental agency (other than the Securities and Exchange Commission in
connection with the aforementioned Registration Statement on Form S-8), or any
other person or entity, without the prior written consent of this firm.


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Board of Directors
CNB Financial Corp.
March 27, 2007
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         We note that, although certain portions of the Registration Statement
on Form S-8 (the financial statements and schedules) have been included therein
(through incorporation by reference) on the authority of "experts" within the
meaning of the Securities Act, we are not experts with respect to any portion of
the Registration Statement, including, without limitation, the financial
statements or schedules or the other financial information or data included
therein.

         We hereby consent to the filing of this opinion as an exhibit to, and
the reference to this firm in, the Company's Registration Statement on Form S-8.

                                            Very truly yours,

                                            /s/ Muldoon Murphy & Aguggia LLP


                                            MULDOON MURPHY & AGUGGIA LLP