Huawei strongly denies the accusations. And it has already built up such a strong lead in 5G technology that it's practically irreplaceable for many wireless carriers that want to be among the first to offer the new services.
"Banning Huawei will create a vacuum that no one can fill in a timely fashion and may seriously impair 5G deployments worldwide," said Stéphane Téral, a mobile telecom infrastructure expert at research firm IHS Markit. The uncertainty is particularly problematic for Europe, where Huawei was expected to play a key role in building 5G networks that the region's leaders say are vital for its economic future.
UK telecom group BT's chief architect, Neil McRae, put the situation in stark terms late last year.
BT (BT) said in December that it won't include Huawei equipment in the heart of its planned 5G network, but will continue to use it for areas that are considered "benign," like the radio masts that connect wireless devices with the core network.
The situation should have Ericsson and Nokia cheering, but experts say the two companies may not be very well positioned to capitalize on Huawei's difficulties.
"It goes without saying that other leading vendors stand to benefit in the short-term," according to analysts at Dell'Oro Group, a market research firm that specializes in telecoms infrastructure analysis.
Ericsson and Nokia both declined to comment on their competitors. Instead, they touted their advancements on 5G in statements to CNN Business.
Nokia claims it holds "the industry's only end-to-end 5G portfolio that is available globally," while Ericsson said it has publicly announced more 5G contracts with operators "than any other vendor."
"From my conversations with carriers, they've found that Huawei is far more advanced than the other two right now," said Dexter Thillien, a senior tech analyst at research firm Fitch Solutions.
Executives at Nokia and Ericsson may also be treading carefully in public for fear of angering the Chinese government and being cut off from its vast market. Nokia, in particular, employs about 15,000 people in China, more than double its headcount of 6,000 in its home country of Finland.
"Their presence there is very, very important for them," Thillien said. "So I don't think they'll go publicly and go and say things like, 'Pick us, because we're European and we're more secure.'"
Even if governments don't block Huawei outright, the possibility of restrictions is casting a shadow over the Chinese company as mobile operators make investment decisions.
"It's probably better technologically — but technology's only one side of the argument," Thillien said. He pointed to Europe as "the big battle right now" for Huawei.
"This situation has created a big bump in Europe's 5G roadmap, while other regions like the Middle East, Africa and Latin America are watching closely," Téral said.
"In the meantime, China and the US are chugging along" with their own rollouts, he added.
Researchers have good reason to believe in Huawei's technical prowess.
It's one of the world's biggest holders of 5G patents and has contributed most to the effort to establish an international standard for 5G, according to IPlytics, a market intelligence firm that tracks tech trends.
Some experts, however, caution that it's too soon to say who's really leading on 5G, mainly because definitions of the technology have yet to be finalized.
"5G is still at the trial stage," said Zhenshan Zhong, who specializes in emerging technology in China for research firm IDC. "Before the test results come out, I don't think anyone can say for definite whether one vendor is actually going to be stronger than the other."
Huawei's size and financial firepower enable it to dwarf its rivals' spending on efforts to come up with new tech.
Ericsson and Nokia's "financial troubles and strategy troubles over the last few years" may have weakened their focus on 5G, Thillien said.
Huawei has the added advantage of being the key player in its vast home market.
Worldwide spending on 5G will balloon from $660 million in 2018 to $70.9 billion in 2022, according to IDC. China alone is expected to account for nearly half of all global 5G expenditure this year, it said.
Huawei's ability to offer more than just network equipment gives it another advantage. It's one of the world's top three smartphone makers, and it also provides cloud computing services and makes artificial intelligence chips.
"Given how all-encompassing 5G is going to be, this 'total-telecom' approach is powerful," said Peter Richardson, a director of tech strategies at research firm Counterpoint. "No other industry player is doing anything similar."