Cisco open-sources AI models for bug hunting

Driving the news: Cisco debuted a new family of small language models, called Antares, that are specifically designed to investigate software repositories and identify where known vulnerabilities exist in a codebase, Amin Karbasi, Cisco's vice president and chief AI scientist, told Axios.

• Cisco says the models performed similarly to much larger models, including OpenAI's GPT-5.5 and Z.ai's GLM-5.2, on Cisco's new benchmark that measures how accurately models identify vulnerable files in real-world software repositories.
• Antares-350M and Antares-1B will be available Tuesday on Hugging Face to users Cisco verifies as cyber defenders.
• Cisco is holding back the public release of a more capable 3-billion-parameter version, Antares-3B, which it plans to integrate into its own security products.

Between the lines: Running large AI models across an organization's codebase can become expensive because defenders may need to rescan repositories as software changes.

• In Cisco's testing, Antares scanned 500 repositories in roughly 15 minutes for less than $1, compared with roughly five hours and more than $100 for GPT-5.5.
• The smaller models are also designed to run locally, allowing organizations to keep sensitive source code inside their own environments instead of sending it to third-party AI providers.
• "You really don't need a private jet to go to your corner store," DJ Sampath, Cisco's senior vice president and general manager of AI software and platform, told Axios. "You want to be able to use something that's practical."

Zoom in: Cisco trained Antares to behave more like a security investigator than a coding assistant, Karbasi said.

• Rather than simply answering questions about code, the models learn how to search a repository, inspect files, change direction when a lead doesn't pan out and narrow in on the files most likely to contain a vulnerability.
• "A vulnerability can be only a few lines of code in a million lines of code," Karbasi said. Antares "is going to be finding these security needles in the haystack of your repository."

• General-purpose language models, by contrast, learn security tasks largely as an extension of broader coding capabilities.

The intrigue: Cisco worked with U.S. government agencies on the models' safety and release, Sampath told Axios.

• The company will also vet who can download the models to ensure adversaries and cybercriminals aren't gaining access to the tools.

The big picture: Cisco is just the latest company to open-source tools designed to find and fix software vulnerabilities. Last week, Capital One open-sourced VulnHunter, an agentic AI security tool that takes an attackers' mindset and reviews source code for the most likely ways a hacker could break in.

What to watch: Cisco is exploring an industry consortium to expand its work on open AI security tools, Sampath said.

• "This is just a starting point," he said.