Los Angeles Lakers governor Jeanie Buss is opposing a potential sale of her family's stake in the franchise to Bob Iger and Joshua Kushner. The dispute emerged in a letter obtained by CNBC.

The letter, written by Buss's attorney Adam Streisand and addressed to law firms representing her siblings Jim, Johnny, Janie, Joey and Jesse, states that Jeanie Buss has not consented to any sale. Streisand wrote that any vote suggesting otherwise "would be and is void."

Streisand argued that Jeanie Buss remains the Lakers' controlling shareholder under a 2017 court order, meaning no sale can proceed without her approval.

"No sale of the JAB Trust's 17.8% ownership interest in the Los Angeles Lakers, Inc. can be effectuated without approval by the current co-trustees, i.e., Jeanie, Janie and Joey Buss," wrote Streisand. "Pursuant to the JAB Trust and the attached Court Order, the co-trustees are bound to vote the Los Angeles Lakers, Inc. shares to ensure that the minimum 15% ownership requirement is maintained in order to ensure that Jeanie Buss may remain Controlling Owner.

"Any attempt by the co-trustees to do otherwise, and any attempt to aid or abet the co-trustees as such, would constitute a breach of trust, breach of fiduciary duty and be in contempt of court."

Iger and Kushner agreed last week to purchase Mark Walter's majority stake in the Lakers in a deal valuing the franchise at $12.5 billion, according to CNBC. Adding the Buss family's stake would have brought their combined ownership to approximately 83 percent, per ESPN.

A person familiar with the matter told CNBC that Jeanie Buss does not wish to sell the family's stake at this time, citing both financial considerations and a desire to preserve her role as governor.