On Thursday, Verizon's general counsel Craig Silliman told a group of reporters that the data breach could trigger a clause in the US$4.83 billion deal that would allow his employer to back out.
This clause says Verizon can pull out if a new event "reasonably can be expected to have a material adverse effect on the business, assets, properties, results of operation or financial condition of the business".
Yahoo! said in a statement: “We are confident in Yahoo!’s value and we continue to work toward integration with Verizon.”
Craig Silliman says Verizon will proceed with the deal based on its "evaluation of the materiality".
But since then, good news has been hard to find for Yahoo!. In September, the company confirmed that the account details of 500 million users had been leaked two years ago.
Then, last week, reports emerged that Yahoo! had acquiesced to a request from either the FBI or the NSA to install a program on its servers to scan emails in order to find specific information.
Silliman said Verizon was evaluating the breach and would make determinations about whether and how to move forward with the deal based on its "evaluation of the materiality".
Verizon chief executive said during the week that his company's investigation into the breach was nearly two-thirds complete.
Last week, the New York Post reported that Verizon was looking to get the Yahoo! sale price lowered by US$1 billion.