CVE-2022-35949

undici.request vulnerable to SSRF using absolute URL on pathname

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

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.

Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside. Typical impact: access to internal metadata services, internal APIs, or cloud credentials.

CVE-2022-35949 has a CVSS score of 5.3 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (5.8.2); upgrading removes the vulnerable code path.

Kodem intelligence

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This issue was fixed in [email protected].

1. What is CVE-2022-35949? CVE-2022-35949 is a medium-severity server-side request forgery (SSRF) vulnerability in undici (npm), affecting versions <= 5.8.1. It is fixed in 5.8.2. Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside.
2. How severe is CVE-2022-35949? CVE-2022-35949 has a CVSS score of 5.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of undici are affected by CVE-2022-35949? undici (npm) versions <= 5.8.1 is affected.
4. Is there a fix for CVE-2022-35949? Yes. CVE-2022-35949 is fixed in 5.8.2. Upgrade to this version or later.
5. Is CVE-2022-35949 exploitable, and should I be worried? Whether CVE-2022-35949 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2022-35949 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2022-35949? Upgrade undici to 5.8.2 or later.

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