CVE-2026-44437
CVE-2026-44437 is a Path Traversal vulnerability in @angular/ssr. O3 Security confirms whether CVE-2026-44437 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Angular SSR: Open Redirect and Request Steering via Encoded X-Forwarded-Prefix
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
@angular/ssrnpmDescription
The Angular SSR is a server-rise rendering tool for Angular applications. From 19.0.0-next.0 to before 19.2.25, 20.3.25, 21.2.9, and 22.0.0-next.7, a vulnerability exists in the X-Forwarded-Prefix header processing logic within Angular SSR. The internal validation mechanism fails to properly account for URL-encoded characters, specifically dots (%2e%2e). This allows an attacker to bypass security filters by injecting encoded path traversal sequences that are later decoded and utilized by the application logic. When an Angular SSR application is configured to trust proxy headers and is deployed behind a proxy that forwards the X-Forwarded-Prefix header without prior sanitization, an attacker can provide a payload such as /%2e%2e/evil. This vulnerability is fixed in19.2.25, 20.3.25, 21.2.9, and 22.0.0-next.7.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @angular/ssr | ≥ 22.0.0-next.0&&< 22.0.0-next.7 | 22.0.0-next.7 |
| 📦npm | @angular/ssr | ≥ 21.0.0-next.0&&< 21.2.9 | 21.2.9 |
| 📦npm | @angular/ssr | ≥ 20.0.0-next.0&&< 20.3.25 | 20.3.25 |
| 📦npm | @angular/ssr | ≥ 19.0.0-next.0&&< 19.2.25 | 19.2.25 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @angular/ssr. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update @angular/ssr to 22.0.0-next.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-44437 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 pinpoints whether CVE-2026-44437 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-44437. 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-2026-44437 in your dependencies?
O3 detects CVE-2026-44437 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.