As Andrew M. Cuomo tries to regain his footing in the race for mayor of New York City, he has embraced an increasingly combative approach, sniping on social media at his biggest opponent, Zohran Mamdani, sometimes multiple times a day.

This weekend, that approach drew widespread attention after Mr. Cuomo, the former governor, took aim at a particularly sensitive issue: Mr. Mamdani’s rent-stabilized apartment.

In a post on X that drew more than 26 million views, Mr. Cuomo wrote that “a single mother and her children slept at a homeless shelter” because Mr. Mamdani, a state assemblyman, was “occupying her rent-controlled apartment.” Mr. Cuomo accused Mr. Mamdani of being “rich,” pointing out that assembly members make more than $140,000, and called on him to “move out.”

In replies to his own post, Mr. Cuomo was more inflammatory, calling Mr. Mamdani “disgusting,” and accused the assemblyman of “callous theft.”

Mr. Cuomo was referring to Mr. Mamdani’s one-bedroom, rent-stabilized apartment in Astoria, Queens, which the assemblyman has said he rents for $2,300 a month. Unlike apartments that rent at market rates, rent-stabilized units tend to be cheaper, with regulated rents that have increases limited by the city’s Rent Guidelines Board. Rent-stabilized tenants basically have a right to renew their lease, meaning they can often stay for as long as they like.

The notion that anyone — including wealthy New Yorkers — can secure those coveted apartments has long been a source of controversy in a city in the throes of a housing crisis.