CVE-2026-5429: CWE-79 Improper neutralization of input during web page generation ('cross-site scripting') in AWS Kiro IDE
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.
AI Analysis
Technical Summary
This vulnerability (CVE-2026-5429) in AWS Kiro IDE is caused by improper neutralization of input during web page generation (CWE-79). Specifically, the color theme name in the Kiro Agent webview is not properly sanitized, enabling cross-site scripting attacks. An attacker can exploit this by crafting a malicious color theme name that executes arbitrary code when a local user opens a trusted workspace and accepts the prompt. The vulnerability affects versions prior to 0.8.140, and a patch has been released in version 0.8.140 to remediate the issue.
Potential Impact
Successful exploitation allows remote unauthenticated attackers to execute arbitrary code in the context of the local user, potentially leading to full compromise of the user's environment within the AWS Kiro IDE. The CVSS score of 7.8 reflects high impact on confidentiality, integrity, and availability. There are no known exploits in the wild at this time.
Mitigation Recommendations
A patch is available in AWS Kiro IDE version 0.8.140 that addresses this vulnerability. Users should upgrade to version 0.8.140 or later to remediate this issue. Until patched, users should exercise caution when opening trusted workspaces and accepting workspace prompts, as this action triggers the vulnerability.
CVE-2026-5429: CWE-79 Improper neutralization of input during web page generation ('cross-site scripting') in AWS Kiro IDE
Description
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.
CVSS v3.1
Score 7.8high
Affected software
AWS
Kiro IDE
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CVE-2026-5429) in AWS Kiro IDE is caused by improper neutralization of input during web page generation (CWE-79). Specifically, the color theme name in the Kiro Agent webview is not properly sanitized, enabling cross-site scripting attacks. An attacker can exploit this by crafting a malicious color theme name that executes arbitrary code when a local user opens a trusted workspace and accepts the prompt. The vulnerability affects versions prior to 0.8.140, and a patch has been released in version 0.8.140 to remediate the issue.
Potential Impact
Successful exploitation allows remote unauthenticated attackers to execute arbitrary code in the context of the local user, potentially leading to full compromise of the user's environment within the AWS Kiro IDE. The CVSS score of 7.8 reflects high impact on confidentiality, integrity, and availability. There are no known exploits in the wild at this time.
Mitigation Recommendations
A patch is available in AWS Kiro IDE version 0.8.140 that addresses this vulnerability. Users should upgrade to version 0.8.140 or later to remediate this issue. Until patched, users should exercise caution when opening trusted workspaces and accepting workspace prompts, as this action triggers the vulnerability.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- AMZN
- Date Reserved
- 2026-04-02T15:46:40.727Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 69cec35ae6bfc5ba1dfb4ce4
Added to database: 04/02/2026, 19:28:26 UTC
Last enriched: 06/05/2026, 19:30:18 UTC
Last updated: 09/12/2026, 10:01:32 UTC
Views: 145
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