CVE-2026-88059

MEDIUM
Published Sep 10, 2026 Modified Sep 11, 2026 CWE-200 CWE-524

Description

Angular is a development platform for building mobile and desktop web applications using TypeScript/JavaScript and other languages. Prior to 20.3.28, 21.2.20, and 22.1.1, Angular's @angular/common HttpTransferCache can cache an authenticated response when Server-Side Rendering (SSR) and hydration use a hierarchical HttpClient configured with withRequestsMadeViaParent. The child TransferCache evaluates an initially anonymous request before delegation, then a parent withInterceptors chain adds an Authorization header, cookie, or API token; although the parent cache skips the authenticated request, the child still stores the private response in TransferState serialized as JSON in the ng-state script. Exploitation requires provideClientHydration, child provideHttpClient delegation through withRequestsMadeViaParent, parent-level credential injection, and an SSR HTML response shared across users by a CDN, reverse proxy, or application cache. A later unauthenticated or unauthorized visitor can receive the cached HTML containing the earlier authenticated user's sensitive response data. Applications can mitigate by attaching credentials at the child, filtering sensitive endpoints with withHttpTransferCacheOptions, disabling transfer caching for sensitive routes, or marking personalized HTML private or no-store. This issue is fixed in versions 20.3.28, 21.2.20, and 22.1.1.

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CVSS v3.1 Score

4.0
MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N

EPSS — Exploit Prediction

0.0030
Probability of exploitation
0.22%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-200 CWE-200
CWE-524 CWE-524

References

Frequently Asked Questions

What is CVE-2026-88059? +
Angular is a development platform for building mobile and desktop web applications using TypeScript/JavaScript and other languages. Prior to 20.3.28, 21.2.20, and 22.1.1, Angular's @angular/common HttpTransferCache can cache an authenticated response when Server-Side Rendering (SSR) and hydration use a hierarchical HttpClient configured with withRequestsMadeViaParent. The child TransferCache evaluates an initially anonymous request before delegation, then a parent withInterceptors chain adds an Authorization header, cookie, or API token; although the parent cache skips the authenticated request, the child still stores the private response in TransferState serialized as JSON in the ng-state script. Exploitation requires provideClientHydration, child provideHttpClient delegation through withRequestsMadeViaParent, parent-level credential injection, and an SSR HTML response shared across users by a CDN, reverse proxy, or application cache. A later unauthenticated or unauthorized visitor can receive the cached HTML containing the earlier authenticated user's sensitive response data. Applications can mitigate by attaching credentials at the child, filtering sensitive endpoints with withHttpTransferCacheOptions, disabling transfer caching for sensitive routes, or marking personalized HTML private or no-store. This issue is fixed in versions 20.3.28, 21.2.20, and 22.1.1. It has a CVSS v3.1 base score of 4.0 (MEDIUM).
How severe is CVE-2026-88059? +
CVE-2026-88059 has a CVSS v3.1 score of 4.0 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0030, placing it in the 0th percentile for exploitation probability.
How do I check if I'm vulnerable to CVE-2026-88059? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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