Bulletin ID: 2026-167-AWS
Scope: AWS
Content Type: Important (requires attention)
Publication Date: 11/03/2026 10:30 AM PST

Description:

maplibre-gl-js-amplify is an open-source AWS Amplify library that integrates Amazon Location Service with MapLibre GL JS to render maps, markers, popups, and geofencing controls in web applications. We identified CVE-2026-121652, where a stored cross-site scripting (XSS) issue in the library's popup and geofence-control rendering. Several code paths interpolated user-controlled GeoJSON feature properties (`title`, address, and place_name) and geofence identifiers directly into the DOM via innerHTML without sanitization. An actor who stored a crafted location record or geofence identifier containing an HTML/JavaScript payload could cause that payload to execute in another user's browser when the corresponding map marker or geofence list item was rendered. In an authenticated session this could enable actions such as session hijacking or data exfiltration in the context of the consuming application.

Impacted versions: <= 4.0.2

Resolution:

This issue has been addressed in maplibre-gl-js-amplify version 4.0.3. The fix introduces an escapeHtml() utility that is applied to all affected user-controlled values before they are inserted into the DOM. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.

Workarounds:

There is no workaround that fully addresses this issue; upgrading to version 4.0.3 or later is required. As defense in depth, applications that cannot upgrade immediately should validate and sanitize all user-supplied location and geofence data (notably title, address, place_name, and geofence identifiers) on input, and apply a restrictive Content Security Policy to limit the impact of injected script.

References:

• CVE-2026-121652
• GHSA-34v3-xxqp-g5g9

Please email aws-security@amazon.com with any security questions or concerns.