These Chinese apps have gained popularity in the US. A TikTok ban could catch them

Lemon8, a photo-sharing app from Bytedance, and RedNote, a Shanghai-based content-sharing platform, have seen an increase in popularity in the US as “TikTok refugees” migrate to alternative platforms ahead of a possible ban.

Now, a law that could shut down TikTok in the U.S. threatens to ensnare these Chinese social media apps and others gaining traction as alternatives to TikTok, legal experts say.

Starting Wednesday, RedNote, known as Xiaohongshu in China — was the top free app in the US iOS store, with Lemon8 taking second place.

The Supreme Court of the United States is preparing to rule on the constitutionality of the Controlled Requests Act to Protect Americans from Foreign Adversariesor PAFACA, that would lead to the TikTok app being banned in the US if its Beijing-based owner, ByteDance, does not sell it by January 19.

While the legislation explicitly names TikTok and ByteDance, experts say its reach is broad and could open the door for Washington to target other Chinese apps.

“Chinese social media apps, including Lemon8 and RedNote, could also end up being banned under this law,” Tobin Marcus, head of US politics and policy at New York-based research firm Wolfe Research, told CNBC.

If the TikTok ban stands, the law will be unlikely to allow potential replacements to originate in China without some form of divestment, experts told CNBC.

PAFACA automatically applies to Lemon8 since it is a subsidiary of ByteDance, while RedNote could fall under the law if its average monthly user base in the U.S. continues to grow, Marcus said.

The legislation prohibits distributing, maintaining or providing Internet hosting services to any “application controlled by a foreign adversary.”

These apps include those connected to ByteDance or TikTok or a social media company controlled by a “foreign adversary” and determined to pose a significant threat to national security.

The language of the legislation is “pretty broad” and would give incoming President Donald Trump room to decide which entities constitute a significant threat to national security, said Carl Tobias, Williams Professor of Law at the University of Richmond.

Xiaomeng Lu, director of geotechnology at political risk consultancy Eurasia Group, told CNBC that the law will likely prevail even if its implementation and enforcement are delayed. Still, he expects Chinese apps in the US to continue to be subject to greater regulatory action in the future.

“The TikTok case has set a new precedent for Chinese apps to be attacked and potentially shut down,” Lu said.

He added that other Chinese apps that could be affected by increased scrutiny this year they include popular Chinese e-commerce platform Temu and Shein. US officials have accused the apps of posing data risksaccusations similar to taxes against TikTok.

TikTok’s fate depends on the Supreme Court after the platform and its parent company filed a lawsuit against the United States government, saying that invoking PAFACA violated constitutional protections of free speech.

TikTok’s argument is that the law is unconstitutional as specifically applied to them, not that it is unconstitutional per se, said Cornell law professor Gautam Hans. “So regardless of whether TikTok wins or loses, the law could still apply to other companies,” he said.

The scope defined by the law is broad enough to apply to a variety of Chinese apps considered a threat to national security, beyond traditional social media apps like TikTok, Hans said.

Meanwhile, Trump has urged the United States Supreme Court postpone the implementation of PAFACA so that he can seek a “political resolution” after taking office. Democratic lawmakers have also urged Congress and President Joe Biden to extend the January 19 deadline.