CVE-2026-104871

MEDIUMCVSS 6.3/10EPSS 0.42%

Last modified

CVE-2026-104871 is a medium-severity vulnerability rated 6.3/10 on the CVSS scale. 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. EPSS estimates a 0.42% chance of exploitation in the next 30 days.

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.

Metrics

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
angularangular-cli< 20.3.36; >= 21.0.0, < 21.2.23; >= 22.0.0, < 22.1.7

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-104871?
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.
How severe is CVE-2026-104871?
CVE-2026-104871 has a CVSS score of 6.3/10 (MEDIUM severity). The EPSS model estimates a 0.42% probability of exploitation in the next 30 days.
How do I fix CVE-2026-104871?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST