A quick summary of the duties a real estate agent owes to each principle when the agent represents both the buyer and seller
Fiduciary Duty Owed to Both Buyer and Seller
In a dual agency relationship the real estate agent owes both the buyer and seller a fiduciary duty of utmost case, integrity, honesty and loyalty in dealings with either the buyer or seller.
Duty of Skill, Honesty, Disclosure Owed to Both Buyer and Seler
A real estate agent representing both the buyer and the seller owes both the buyer and seller an obligation 1) of diligent exercise of reasonable skill in performance of their duties, 2) honesty, fair dealing, and good faith, and 3) to disclose all facts known to the agent materially affecting the value or desirability of the property.
What a Dual Agent Cannot Disclose
A dual agent cannot disclose to the other party without consent is what the seller is willing to sell the property for below the list price, what the buyer is willing to pay above the price offered, and any confidential information obtained by the other party that does not violate their duties.
Additional resources provided by the author
The California Bureau of Real Estate has many guides to help explain the law of agency. Below is a link for much more detailed information.