Amazon Web Services says a December 2025 disruption to AWS Cost Explorer “was the result of user error—specifically misconfigured access controls—not AI,” disputing claims that its Kiro AI coding tool caused the outage.
A reported account citing four people familiar with the matter described a roughly 13-hour interruption to an AWS system used by customers in mid-December after engineers allowed Kiro to make changes. The people said the tool determined that the best course of action was to “delete and recreate the environment.”
AWS described the disruption as “extremely limited,” saying it affected only Cost Explorer, which helps customers track cloud costs and usage, in one of its two regions in mainland China. The company said compute, storage, databases and AI services were unaffected.
AWS attributes the incident to access controls
Amazon attributed the problem to a misconfigured role and said the same issue could occur with another developer tool or a manual action. AWS said the engineer involved had been using a role with broader permissions than expected.
The company said users must configure which actions Kiro can take and that the tool requests authorization before acting by default. AWS said it subsequently implemented additional safeguards, including mandatory peer review for production access.
Second reported incident remains disputed
The reporting also cited multiple Amazon employees who described a separate production incident in recent months involving Amazon Q. AWS said that event did not affect a customer-facing AWS service. In its public response, Amazon also denied that a second event had affected AWS.
