CVE-2025-62427 — @angular/ssr
Fix: angular/angular-cli@5271547CVE-2025-62427 is a security vulnerability in @angular/ssr. A fix is available for @angular/ssr — see the affected versions and patch details below.
Server-Side Request Forgery (SSRF) in Angular SSR
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-62427.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@angular/ssrnpmDescription
Impact
The vulnerability is a Server-Side Request Forgery (SSRF) flaw within the URL resolution mechanism of Angular's Server-Side Rendering package (@angular/ssr).
The function createRequestUrl uses the native URL constructor. When an incoming request path (e.g., originalUrl or url) begins with a double forward slash (//) or backslash (\\), the URL constructor treats it as a schema-relative URL. This behavior overrides the security-intended base URL (protocol, host, and port) supplied as the second argument, instead resolving the URL against the scheme of the base URL but adopting the attacker-controlled hostname.
This allows an attacker to specify an external domain in the URL path, tricking the Angular SSR environment into setting the page's virtual location (accessible via DOCUMENT or PlatformLocation tokens) to this attacker-controlled domain. Any subsequent relative HTTP requests made during the SSR process (e.g., using HttpClient.get('assets/data.json')) will be incorrectly resolved against the attacker's domain, forcing the server to communicate with an arbitrary external endpoint.
Exploit Scenario
A request to http://localhost:4200//attacker-domain.com/some-page causes Angular to believe the host is attacker-domain.com. A relative request to api/data then becomes a server-side request to http://attacker-domain.com/api/data.
Patches
@angular/ssr19.2.18@angular/ssr20.3.6@angular/ssr21.0.0-next.8
Mitigation
The application's internal location must be robustly determined from the incoming request. The fix requires sanitizing or validating the request path to prevent it from being interpreted as a schema-relative URL (i.e., ensuring it does not start with //).
Server-Side Middleware
If you can't upgrade to a patched version, implement a middleware on the Node.js/Express server that hosts the Angular SSR application to explicitly reject or sanitize requests where the path begins with a double slash (//).
Example (Express/Node.js):
// Place this middleware before the Angular SSR handler
app.use((req, res, next) => {
if (req.originalUrl?.startsWith('//')) {
// Sanitize by forcing a single slash
req.originalUrl = req.originalUrl.replace(/^\/\/+/, '/');
req.url = req.url.replace(/^\/\/+/, '/');
}
next();
});
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @angular/ssr | ≥ 19.0.0-next.0&&< 19.2.18 | 19.2.18npm install @angular/ssr@19.2.18 |
| 📦npm | @angular/ssr | ≥ 20.0.0-next.0&&< 20.3.6 | 20.3.6npm install @angular/ssr@20.3.6 |
| 📦npm | @angular/ssr | ≥ 21.0.0-next.0&&< 21.0.0-next.8 | 21.0.0-next.8npm install @angular/ssr@21.0.0-next.8 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @angular/ssr, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @angular/ssr to 19.2.18 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-62427 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-62427 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-62427. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-62427 in your dependencies?
O3 Security finds CVE-2025-62427 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.