LONDON — Tech giant Google has raised the alarm over a wave of extortion emails sent to high-level executives, with hackers claiming to hold stolen corporate data. Despite the bold claims, Google admitted it could not confirm whether the hackers had actually accessed any data. Google described the email campaign as “high-volume” but declined to share how many executives had been targeted or which sectors were most affected. The Cl0p group has been linked to several high-profile cyberattacks in recent years, including incidents involving government agencies and large corporations. Cybersecurity professionals urge companies to be vigilant, even if the credibility of the hackers’ claims is still in question.