CVE-2022-35949
MEDIUMCVE-2022-35949 is a medium-severity (CVSS 5.3) Server-Side Request Forgery (SSRF) vulnerability in undici. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether CVE-2022-35949 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
`undici.request` vulnerable to SSRF using absolute URL on `pathname`
Blast Radius
undiciReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
undici is an HTTP/1.1 client, written from scratch for Node.js.undici is vulnerable to SSRF (Server-side Request Forgery) when an application takes in user input into the path/pathname option of undici.request. If a user specifies a URL such as http://127.0.0.1 or //127.0.0.1 js const undici = require("undici") undici.request({origin: "http://example.com", pathname: "//127.0.0.1"}) Instead of processing the request as http://example.org//127.0.0.1 (or http://example.org/http://127.0.0.1 when http://127.0.0.1 is used), it actually processes the request as http://127.0.0.1/ and sends it to http://127.0.0.1. If a developer passes in user input into path parameter of undici.request, it can result in an SSRF as they will assume that the hostname cannot change, when in actual fact it can change because the specified path parameter is combined with the base URL. This issue was fixed in [email protected]. The best workaround is to validate user input before passing it to the undici.request call.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | undici | all versions | 5.8.2 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for undici. 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 undici to 5.8.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-35949 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-2022-35949 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-2022-35949. 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-2022-35949 in your dependencies?
O3 detects CVE-2022-35949 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.