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[ CVE-2026-104871 · Published 2 Oct 2026 ]

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

CVSS 6.3 EPSS <1%1 agency advisoryFix available

[ Description ]Official 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.

[ Fixes ]Fixes and patches

  • @angular/ssr 22.1.7Fixed version · GitHub Advisories · npm package @angular/ssr: upgrade to 22.1.7 or later (affected >= 22.0.0, < 22.1.7)
  • @angular/ssr 21.2.23Fixed version · GitHub Advisories · npm package @angular/ssr: upgrade to 21.2.23 or later (affected >= 21.0.0, < 21.2.23)
  • @angular/ssr 20.3.36Fixed version · GitHub Advisories · npm package @angular/ssr: upgrade to 20.3.36 or later (affected >= 20.0.0, < 20.3.36)

[ Advisories ]Government CERT advisories

[ Packages ]Affected open-source packages

[ References ]References