Daily Briefing for 04.29.26

Top stories.

1. OpenAI and Anthropic brief Congress on cyber-capable AI models.
2. Rival ransomware gangs list each other as victims.
3. Business news: Silverfort will acquire Fabrix Security.

OpenAI and Anthropic brief Congress on cyber-capable AI models.

OpenAI and Anthropic each met with US House Homeland Security Committee staff last week to brief them on the security implications of Mythos Preview and GPT-5.4-Cyber, Axios reports. Both companies are limiting the release of their cyber-focused AI models to prevent abuse by malicious actors.

A committee aide told Axios the briefings were "proactive engagement with these companies on recent frontier model developments." An Anthropic spokesperson said the company regularly briefs "congressional staff on model capabilities and their national security implications." OpenAI said it met with both Senate and House committees last week, as well as with the White House. House Homeland Security Chair Andrew Garbarino (Republican of New York) said the briefings are meant to ensure that "Congress is asking the right questions."

Axios also reports that the White House is drafting guidance to help government agencies get around Anthropic's designation as a supply chain risk and start using the company's advanced AI models, including Mythos. A source told Axios that the efforts are a way to "save face and bring 'em back in." The White House said in a statement, "The White House continues to proactively engage across government and industry to protect our country and the American people, including by working with frontier AI labs. The collective effort of all involved will ultimately benefit our economy and country. However, any policy announcement will come directly from the President and anything else is pure speculation."

Rival ransomware gangs list each other as victims.

Halcyon says two rival ransomware-as-a-service operations, 0APT and KryBit, have started posting each other's internal data on their respective leak sites. 0APT is also posting data allegedly stolen from the Everest and RansomHouse ransomware groups. Everest and RansomHouse are established ransomware gangs that have been active for years, while KryBit is an emerging threat with around twenty victims. 0APT, on the other hand, has only posted fabricated data from fake attacks in a failed attempt to attract affiliates.

Halcyon notes, "This type of activity is unusual: 0APT used their initially failing affiliate operation and turned it against not only KryBit, but other ransomware operators. However, the impact on Everest and RansomHouse operations was little to none. KryBit instead retaliated and took over full control of the 0APT data leak site. Both 0APT and KryBit operations likely will now attempt to move and rebuild their infrastructure because of the significant impact of the leaks on each of their operations."

Business news: Silverfort will acquire Fabrix Security.

Dallas, Texas-based identity security firm Silverfort has agreed to acquire Israeli agentic AI security company Fabrix Security. Fabrix CEO Raz Rotenberg stated, "By joining Silverfort, we can combine our technology with Silverfort’s platform to create something no one has achieved before: autonomous runtime Identity Security. Together, we’ll be the first to bring to the market this next generation of Identity Security—one that can truly stand up to AI-driven adversaries without slowing the business."