Which versions of AWS are affected by EUVD-2026-18519?

AWS Kiro IDE versions before 0.8.140 contain an arbitrary code execution vulnerability triggered when users open malicious workspace files with crafted color theme names, requiring user interaction…. A patch is available.

How to fix or mitigate EUVD-2026-18519?

Within 24 hours: Inventory all Kiro IDE installations and identify systems running versions prior to 0.8.140. Within 7 days: Update AWS Kiro IDE to version 0.8.140 or later on all affected systems; validate installations post-patch. Within 30 days: Review workspace file sharing practices and implement controls restricting workspace opening to trusted internal sources only; document baseline of applied patch status for compliance records.

AWS EUVD-2026-18519

Q: What is the CVSS score of EUVD-2026-18519?

EUVD-2026-18519 has a CVSS 4.0 base score of 7.1 (High). CVSS vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.0%.

| CVE-2026-5429 HIGH

Cross-site Scripting (XSS) (CWE-79)

2026-04-02 AMZN

GHSA-7v7j-vpv5-h468

XSS RCE AWS Kiro Ide

7.1

CVSS 4.0 · Vendor: AMZN

Severity by source

Vendor (AMZN) PRIMARY

7.1 HIGH

CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from Vendor (AMZN) · only source for this CVE.

CVSS VectorVendor: AMZN

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Scope

Lifecycle Timeline

Analysis Updated

Apr 16, 2026 - 06:08 EUVD-patch-fix

executive_summary

Re-analysis Queued

Apr 16, 2026 - 05:29 backfill_euvd_patch

patch_released

Patch available

Apr 16, 2026 - 05:29 EUVD

0.8.140

EUVD ID Assigned

Apr 02, 2026 - 19:01 euvd

EUVD-2026-18519

Analysis Generated

Apr 02, 2026 - 19:01 vuln.today

CVE Published

Apr 02, 2026 - 18:37 nvd

HIGH 7.1

DescriptionCVE.org

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.

AnalysisAI

Arbitrary code execution in AWS Kiro IDE versions prior to 0.8.140 occurs when a local user opens a maliciously crafted workspace containing an unsanitized color theme name, exploiting improper neutralization of input during webview generation. The attack requires user interaction (trusting the workspace when prompted) and can deliver full system compromise with high confidentiality, integrity, and availability impact. No public exploit identified at time of analysis, though SSVC framework rates technical impact as total with manual (non-automatable) exploitation potential.

Technical ContextAI

This vulnerability stems from CWE-79 (Improper Neutralization of Input During Web Page Generation, commonly known as Cross-Site Scripting) affecting the Kiro Agent webview component within AWS Kiro IDE. The affected component fails to sanitize user-controlled input in workspace configuration files-specifically color theme names-before rendering them in the IDE's webview interface. While classified as XSS, the technical impact escalates to arbitrary code execution because the webview operates within the Electron-like IDE environment with access to native system APIs. The CPE identifier (cpe:2.3:a:aws:kiro_ide) confirms this affects AWS's Kiro IDE product across all versions from 0.1 through builds preceding 0.8.140. The CVSS 4.0 vector indicates local attack vector (AV:L) requiring user interaction (UI:A) with present attack complexity (AT:P), meaning the attack depends on specific timing or conditions-in this case, the user explicitly trusting the malicious workspace.

RemediationAI

Upgrade immediately to AWS Kiro IDE version 0.8.140 or later, which contains input sanitization fixes for webview rendering of workspace configuration parameters. The official patch is documented in the Kiro IDE changelog at https://kiro.dev/changelog/ide/0-8/#patch-0-8-140 with implementation details available in AWS Security Bulletin 2026-012 at https://aws.amazon.com/security/security-bulletins/2026-012-aws/. Organizations unable to upgrade immediately should implement compensating controls including restricting workspace sources to trusted internal repositories, enforcing mandatory security reviews of workspace configuration files before distribution, and educating developers to scrutinize workspace trust prompts especially when opening projects from external or unknown sources. Disable automatic workspace trust features if available in older versions and require explicit administrator approval for workspace activation in sensitive development environments.