かねない is used when you think there is a real risk that some negative event will occur. It's often translated as 'might' or 'could well', but it carries a judgment that the outcome is undesirable or dangerous. You'll hear it in warnings, predictions, or cautious comments.

Because it focuses on negative possibilities, it's not used for positive outcomes. You wouldn't say 彼は成功しかねない to mean 'he might succeed' with a positive tone. Stick to situations where the speaker is concerned or wary.

This is a written and spoken form, but it leans slightly formal. In casual conversation you might hear it, but it's more common in news, reports, or serious discussions.