CVE-2026-9255
Bulletin ID: 2026-035-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 05/22/2026 09:45 AM PDT Description: Kiro CLI is a command-line AI coding assistant that enables developers to interact with AI models to execute code, manage files, and run shell commands. We identified CVE-2026-9255, an issue where missing input source validation in the tool authorization prompt could allow a local actor to execute arbitrary tools, including shell commands, without user approval by crafting content that is piped to kiro-cli via stdin. Impacted versions: kiro-cli prior to 1.28.0 Please refer to the article below for the most up-to-date and complete information related to this AWS Security Bulletin.
CSIRTS triage
- What
- Missing input source validation could allow local actors to execute arbitrary tools without user approval.
- Who is affected
- Users of Kiro CLI versions prior to 1.28.0.
- Urgency
- Remediation is urgent as it allows unauthorized tool execution.
- Action
- Upgrade Kiro CLI to version 1.28.0 or later.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Low exploitation risk0.12% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 2% of all EPSS-scored CVEs.
Advisory coverage (1)
- unknownCVE-2026-9255 - Tool Execution Without Authorization via Piped Stdin in Kiro CLIaws · 2026-06-05
External references
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[](https://www.csirts.com/cve/CVE-2026-9255)