Twitter whistleblower Peiter “Mudge” Zatko told the US Senate on Tuesday that the company's failure to address risks was a “ticking bomb” for national security.
“When an influential media platform can be compromised by teenagers, thieves and spies, and the company repeatedly creates security problems on their own, this is a big deal for all of us,” he told the Senate judiciary committee.
The social media company's shareholders on Tuesday voted to approve the Tesla founder's merger agreement.
Mr Zatko told senators that the executive leadership at Twitter had failed to respond to security concerns because of a lack of competency and because the goal was to give priority to profits.
The company's leadership is “misleading the public, lawmakers, regulators and even its own board of directors”, he said.
Twitter was also more than a decade behind the industry's best security standards, Mr Zatko said.
One issue that was not discussed during the hearing was whether Twitter is accurately counting its active users.
Mr Musk has said without evidence that many of the platform's 238 million daily users are spam bots.
The Delaware judge overseeing the case ruled last week that he could include new evidence related to Mr Zatko's allegations.
During the hearing Mr Musk tweeted a popcorn emoji, suggesting he was tuned into the day's proceedings.
Mr Zatko was the head of security at Twitter until he was fired this year for what the company called “ineffective leadership and poor performance”.
The company also said his claims were designed to harm the company. Mr Zatko's claims have not been corroborated.
He filed a whistleblower complaint with Congress, the Justice Department and other federal agencies in July, accusing Twitter of falsely claiming it had enacted stronger security measures to protect user privacy.
Disclosures from Mr Zatko also showed that at least one Chinese agent is employed at the company, Chuck Grassley, a Republican US senator from Iowa, said in his opening remarks during a hearing on Tuesday.
The disclosures “paint a disturbing picture of a company that’s solely focused on profits at any expense”, Mr Grassley said.
He said Twitter chief executive Parag Agrawal was invited to the hearing to respond to the allegations, but declined for what he claimed to be fear that it would interfere with the company's civil litigation against Mr Musk.
Agencies contributed to this report