It's one thing Huawei's products have severe vulnerabilities (as every other IT companies do), and another thing the company is actively engaging in espionage.
If this is the best hard evidence the US can bring forward, then the whole allegation sounds entirely political-driven.
There is none in recent years. Huawei even offered to open its complete source code to the US government for inspection but got turned down.
There is evidence that the US spy agency hacked in Huawei HQ for years and still the US cannot produce evidence of Huawei wrongdoing. But then again it's possible the US don't want to disclose it's intel source.
If this is the best hard evidence the US can bring forward, then the whole allegation sounds entirely political-driven.