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High, CVSS 8.7amended

Angular: SSRF via protocol-relative and backslash URLs in Angular Platform-Server

CVE-2026-41423GHSA-45q2-gjvg-7973

What to do

Partial vendor fix. Follow the primary source's mitigation guidance and check back for a fix.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

  • npm @angular/platform-server

    Affected
    >= 22.0.0-next.0, < 22.0.0-next.8>= 21.0.0-next.0, < 21.2.9>= 20.0.0-next.0, < 20.3.19>= 19.0.0-next.0, < 19.2.21<= 18.2.14
    Fixed in
    21.2.9, 20.3.19, 22.0.0-next.8, 19.2.21

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS 4.0
8.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:L/SI:L/SA:N · score source
EPSS
  • CVE-2026-41423: 0.30% estimated exploitation activity in the next 30 days; percentile 23.31 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Impact A Server-Side Request Forgery (SSRF) vulnerability exists in @angular/platform-server due to improper handling of URLs during Server-Side Rendering (SSR). When an attacker sends a request such as GET /\evil.com/ HTTP/1.1 the server engine (Express, etc.) passes the URL string to Angular’s rendering functions. Because the URL parser normalizes the backslash to a forward slash for HTTP/HTTPS schemes, the internal state of the application is hijacked to believe the current origin is evil.com. This misinterpretation tricks the application into treating the attacker’s domain as the local origin. Consequently, any relative HttpClient requests or PlatformLocation.hostname references are redirected to the attacker controlled server, potentially exposing internal APIs or metadata services. Affected APIs: - renderModule - renderApplication - CommonEngine (from @angular/ssr) Non-Affected APIs: - AngularAppEngine (from @angular/ssr) - AngularNodeAppEngine (from @angular/ssr) Attack…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 3 · amended ·

    Amended from ghsa record GHSA-45q2-gjvg-7973

  2. Revision 2 · amended ·

    Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

  3. Revision 1 · created ·

    Published from osv record GHSA-45q2-gjvg-7973

Agent brief

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# Patch Next advisory brief: CVE-2026-41423

Advisory: Angular: SSRF via protocol-relative and backslash URLs in Angular Platform-Server
IDs: CVE-2026-41423, GHSA-45q2-gjvg-7973
Record: https://patchnext.com/advisories/cve-2026-41423 (revision 3, source checked 26 Oct 2026, 12:51 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Partial vendor fix; fixed versions by package: @angular/platform-server 22.0.0-next.8, 21.2.9, 20.3.19, 19.2.21. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @angular/platform-server: affected >= 22.0.0-next.0, < 22.0.0-next.8; >= 21.0.0-next.0, < 21.2.9; >= 20.0.0-next.0, < 20.3.19; >= 19.0.0-next.0, < 19.2.21; <= 18.2.14; fixed in 21.2.9, 20.3.19, 22.0.0-next.8, 19.2.21

## Suggested inspection (read-only)
- `npm ls @angular/platform-server --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @angular/platform-server.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-45q2-gjvg-7973 (OSV record GHSA-45q2-gjvg-7973 lists affected ranges: npm @angular/platform-server >=22.0.0-next.0 =21.0.0-next.0 =20.0.0-next.0 =19.0.0-next.0 =0 <=18.2.14)
- Verified: https://github.com/advisories/GHSA-45q2-gjvg-7973 (GitHub-reviewed advisory GHSA-45q2-gjvg-7973 lists affected ranges: npm @angular/platform-server >=22.0.0-next.0 =21.0.0-next.0 =20.0.0-next.0 =19.0.0-next.0 =0 <=18.2.14)

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