While the company was blasted for its opaque relationship with China's government in a U.S. intelligence report released Monday, a bigger worry for some is what's inside its routers.

"The code quality is pretty much from the '90s," said Lindner, who has analyzed the software inside Huawei's home and enterprise routers, and runs , a security consultancy, in Berlin.

Lindner will speak on Thursday at the Hack in the Box security conference in Kuala Lumpur and discuss some of the vulnerabilities he and a fellow researcher disclosed earlier this year along with an overview of Huawei's security.

When Lindner began looking at Huawei's routers, the company didn't have a prominent product security team, Lindner said. But since he and colleague Gregor Kopf in the firmware of Huawei's AR18 series routers, which are meant for homes, and its AR29 series routers, intended for small enterprises, at the Defcon conference in July, "they seem to be trying to ramp up product security in a visible way right now," he said.

Lindner's conclusion comes as Huawei is a blistering report released this week by the U.S. House of Representatives' Permanent Select Committee on Intelligence. The report alleges that Huawei and another Chinese company, ZTE, pose a threat to U.S. infrastructure and postulates their equipment could be secretly modified by Chinese intelligence agencies.