WASHINGTON, May 1 : U.S. cybersecurity officials are considering sharply shorter deadlines for fixing critical flaws in government IT systems, amid concerns hackers could exploit them using artificial‑intelligence tools such as Anthropic’s Mythos, people familiar with the matter said.  The move, which has not been previously reported, would slash the deadline for responding to actively exploited vulnerabilities from an average of two or three weeks to three days, the people said. Anxiety over the power and proliferation of AI models like Mythos and OpenAI’s GPT‑5.4‑Cyber has been building for weeks. Although hackers have been deploying AI since at least 2023, these newer models are said to be able to easily identify previously unknown vulnerabilities or seize on freshly disclosed ones to enable complex hacking operations. So while it previously might have taken hackers several months, weeks, or days to take advantage of software flaws, that timeframe has been compressed, in at least some cases, to a matter of hours. That in turn is putting pressure on defenders to kick into high gear, said Stephen Boyer, …