CVE-2026-5429

Arbitrary code execution via unsanitized theme name

Published Apr 2, 2026 · Updated Apr 2, 2026

Cross-site scripting in the Kiro Agent webview in Kiro IDE before 0.8.140 allows remote attackers to execute arbitrary code. The webview inserts a workspace-controlled color theme name into generated page content without neutralizing executable markup. Execution occurs only after a local user opens the crafted workspace and accepts its trust prompt, exposing the user's local IDE context.

CVSS severity7.1
High
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in the Kiro Agent webview in Kiro IDE before 0.8.140 allows remote attackers to execute arbitrary code. The webview inserts a workspace-controlled color theme name into generated page content without neutralizing executable markup. Execution occurs only after a local user opens the crafted workspace and accepts its trust prompt, exposing the user's local IDE context.

The record

CVE
CVE-2026-5429
Published
Apr 2, 2026
Updated
Apr 2, 2026
Vendor
Amazon Web Services
Product
Kiro IDE
Classifications
CWE-79, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 2, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.1 <0.8.140

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Amazon Web Services · Kiro IDEversion=0.1 <0.8.140

Published CVSS scores

7.8Amazon Web ServicesCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
7.1Amazon Web ServicesCVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1204.002Malicious File

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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