CVE-2026-5429
Bulletin ID: 2026-012-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 2026/04/02 11:30 AM PDT Description: Kiro IDE is an agentic development environment that makes it easy for developers to ship real engineering work with the help of AI agents. We identified CVE-2026-5429, where unsanitized input during web page generation in the Kiro Agent webview in Kiro IDE before version 0.8.140 allows a remote unauthenticated threat actor to execute arbitrary code via a maliciously crafted color theme name when a local user opens the workspace. This issue requires the user to trust the workspace when prompted. Impacted versions: < 0.8.140 Please refer to the article below for the most up-to-date and complete information related to this AWS Security Bulletin.
CSIRTS triage
- What
- Unsanitized input during web page generation allows a remote unauthenticated threat actor to execute arbitrary code via a maliciously crafted color theme name.
- Who is affected
- Users of Kiro IDE versions before 0.8.140.
- Urgency
- Remediation is urgent due to the risk of arbitrary code execution via XSS.
- Action
- Upgrade to Kiro IDE version 0.8.140 or later.
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Exploitation outlook
- Low exploitation risk0.16% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 5% of all EPSS-scored CVEs.
Advisory coverage (1)
- unknownCVE-2026-5429 - Kiro IDE Webview Cross-Site Scripting via Workspace Color Themeaws · 2026-06-05
External references
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[](https://www.csirts.com/cve/CVE-2026-5429)