# CVE-2026-5429: AWS Kiro IDE arbitrary code execution in Kiro Agent webview

Source: https://junglewise.ai/threats/cve-2026-5429-aws-kiro-ide-arbitrary-code-execution-in-kiro-agent-webview  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-02. Updated: 2026-07-24  
License: CC BY 4.0 with a link back

CVE-2026-5429 · Severity: high · CVSS 7.8 · Published 2026-04-02

Kiro IDE is a development environment that uses AI agents to assist with software engineering tasks. A security flaw allows a malicious actor to execute unauthorized code on a developer's machine if the developer opens a specially crafted workspace and chooses to trust it. This could lead to a full system compromise, data theft, or unauthorized access to source code.

Technologies: [Amazon AWS](https://junglewise.ai/threats/technologies/aws), [AWS Kiro IDE](https://junglewise.ai/threats/technologies/kiro-ide). Vendors: [Amazon](https://junglewise.ai/threats/vendors/amazon), [AWS](https://junglewise.ai/threats/vendors/aws).

## Quick answers

**Is CVE-2026-5429 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-5429 being exploited in the wild.

**How severe is CVE-2026-5429?** High severity, with a CVSS score of 7.8, published 2 April 2026.

**Which products and versions are affected?** AWS Kiro IDE before 0.8.140.

**Is there a fix for CVE-2026-5429?** A patch was published on 2026-04-02: Fixed in version 0.8.140 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-5429 attacked?** It is attacked with local access, in a network appliance.

**Am I affected by CVE-2026-5429?** Check whether you run Amazon AWS or AWS Kiro IDE at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A Cross-Site Scripting (XSS) vulnerability (CWE-79) exists in the Kiro Agent webview component of Kiro IDE due to improper neutralization of input during web page generation. An attacker can exploit this by crafting a workspace with a malicious color theme name. When a local user opens this workspace and accepts the 'trust workspace' prompt, the unsanitized theme name is processed by the webview, leading to arbitrary code execution. The vulnerability is resolved in version 0.8.140.

## Affected products

- AWS Kiro IDE before 0.8.140

## Timeline

- 2026-04-02: disclosed
- 2026-04-02: advisory
- 2026-04-02: patched: Fixed in version 0.8.140

## References

- [https://aws.amazon.com/security/security-bulletins/2026-012-aws/](https://aws.amazon.com/security/security-bulletins/2026-012-aws/)
- [https://kiro.dev/changelog/ide/0-8/](https://kiro.dev/changelog/ide/0-8/)

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