Amazon AWS Kiro IDE up to 0.8.139 Kiro Agent Webview cross site scripting

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.5$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as problematic, was found in Amazon AWS Kiro IDE up to 0.8.139. This vulnerability affects unknown code of the component Kiro Agent Webview. Such manipulation leads to cross site scripting. This vulnerability is listed as CVE-2026-5429. The attack must be carried out locally. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Amazon AWS Kiro IDE up to 0.8.139 and classified as problematic. Affected by this issue is some unknown functionality of the component Kiro Agent Webview. The manipulation with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. CVE summarizes:

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 potentially damaging crafted color theme name when a local user opens the workspace. This issue requires the user to trust the workspace when prompted. To remediate this issue, users should upgrade to version 0.8.140.

The advisory is shared for download at aws.amazon.com. This vulnerability is handled as CVE-2026-5429 since 04/02/2026. The exploitation is known to be easy. The attack needs to be approached locally. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1059.007.

Upgrading to version 0.8.140 eliminates this vulnerability. The upgrade is hosted for download at kiro.dev.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-18519). Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 5.5
VulDB Meta Temp Score: 5.5

VulDB Base Score: 3.3
VulDB Temp Score: 3.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.8
CNA Vector (AMZN): 🔒

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Cross site scripting
CWE: CWE-79 / CWE-94 / CWE-74
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: AWS Kiro IDE 0.8.140

Timelineinfo

04/02/2026 CVE reserved
04/02/2026 +0 days VulDB entry created
04/03/2026 +0 days Advisory disclosed
07/27/2026 +115 days VulDB entry last update

Sourcesinfo

Advisory: aws.amazon.com
Status: Confirmed

CVE: CVE-2026-5429 (🔒)
GCVE (CVE): GCVE-0-2026-5429
GCVE (VulDB): GCVE-100-355028
EUVD: 🔒

Entryinfo

Created: 04/03/2026 00:06
Updated: 07/27/2026 14:38
Changes: 04/03/2026 00:06 (77), 04/03/2026 01:54 (1), 07/27/2026 14:38 (1)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Do you want to use VulDB in your project?

Use the official API to access entries easily!