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OpenAdvisories
Medium · 6.3 CVE-2026-104871 EUVD-2026-91778GHSA-7g7c-h8rr-7p6q

Angular SSR: Path Traversal to Sibling Directories in CommonEngine on Windows

Published Oct 2, 2026 · Updated Oct 2, 2026 · Assigned by GitHub_M

Description

The Angular SSR is a server-rise rendering tool for Angular applications. Prior to versions 20.3.36, 21.2.23, and 22.1.7, the CommonEngine retrieveSSGPage prerendered-page retrieval logic in @angular/ssr/node, and in @angular/ssr for versions 17 through 18, accepts a relative request URL containing a backslash parent-traversal segment on Windows. The non-special resolve:// URL base preserves the backslash, path.join interprets it as a Windows separator, and the pagePath.startsWith(normalize(publicPath)) check incorrectly accepts a sibling output directory whose name shares the configured public-directory prefix. An unauthenticated requester can therefore retrieve a sibling prerendered HTML page when that page contains the Angular SSG marker. The issue is limited to Windows deployments that pass relative request URLs to CommonEngine.render, have a prefix-sharing sibling output directory, and contain qualifying prerendered Angular HTML; it does not provide arbitrary file read. This issue is fixed in versions 20.3.36, 21.2.23, and 22.1.7.

Affected products

VendorProductAffectedFixed
angular angular-cli < 20.3.36, >= 21.0.0, < 21.2.23, >= 22.0.0, < 22.1.7 —

Affected packages

EcosystemPackageAffectedFixedRecord
npm @angular/ssr >= 22.0.0, < 22.1.7 22.1.7 GHSA-7g7c-h8rr-7p6q
npm @angular/ssr >= 21.0.0, < 21.2.23 21.2.23 GHSA-7g7c-h8rr-7p6q
npm @angular/ssr >= 20.0.0, < 20.3.36 20.3.36 GHSA-7g7c-h8rr-7p6q
npm @angular/ssr <= 19.2.27 — GHSA-7g7c-h8rr-7p6q

Advisories 1

References