Hackers hit AI coding tool OpenCode, running up charges on users’ AI accounts

OpenCode, an open-source AI coding agent that has been gaining ground among developers as an alternative to Claude Code and Cursor, said Saturday that attackers broke into an older system overnight, affecting 1.4% of users of its online platform, OpenCode Console, where some users store the API keys, or digital passwords, they use to access AI services.

As the OpenCode team struggled to keep pace with the attack, the scramble to respond highlighted a growing problem: companies without vetted access to AI models with fewer safety restrictions have a hard time defending against large-scale, AI-driven cyberattacks.

“We had a security breach last night related to a large-scale distillation attack that impacted 1.4% of OpenCode Console users,” the company wrote on X. “We have notified them all this morning via email.” Users who did not receive an email were not impacted, the company said.

While the company didn’t specify how the distillation attack occurred, leaked API keys can help users in countries with restricted access to American models generate the high volume of outputs needed for that process. Some skeptics called the framing an overstretch, arguing that the incident was a straightforward breach whose use for distillation remains unproven.

Overnight, developers began posting spending alerts and unauthorized charges on Reddit and X. “I saw my Open AI, Anthropic, and Google AI spend alerts all fire off before going to bed wondering what was going on,” a developer wrote. 

Other users reported charges in the hundreds of dollars on individual accounts; a few described totals above $1,000.

Anthropic and Google both blocked the API keys they believed were exposed, while OpenAI said it worked with OpenCode to restore access and refund its API customers for credits used in the attack. OpenCode said refunds for unauthorized charges are underway.

“[T]hat was a bit frustrating,” he wrote on X.

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