CVE-2022-35949 is a medium-severity (CVSS 5.3) Server-Side Request Forgery (SSRF) vulnerability in undici. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for undici — see the affected versions and patch details below.
`undici.request` vulnerable to SSRF using absolute URL on `pathname`
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.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2022-35949.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
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.
undicinpmDescription
Impact
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
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.
Patches
This issue was fixed in [email protected].
Workarounds
The best workaround is to validate user input before passing it to the undici.request call.
For more information
If you have any questions or comments about this advisory:
- Open an issue in undici repository
- To make a report, follow the SECURITY document
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | undici | all versions | 5.8.2npm install undici@5.8.2 |
Affected Products
undicinodejsResearch 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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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
Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Validate user input before passing it to the `undici.request` call.Source: Red Hat security advisory for CVE-2022-35949 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2022-35949 in your dependencies?
Find it across npm, including transitive dependencies.