Affected versions of yjmyjmyjm resolve relative file paths, resulting in a directory traversal vulnerability. A malicious actor can use this vulnerability to access files outside of the intended directory root, which may result in the disclosure of private files on the vulnerable system.

Example request:

GET /../../../../../../../../../../etc/passwd HTTP/1.1
host:foo

Recommendation

No patch is available for this vulnerability.

It is recommended that the package is only used for local development, and if the functionality is needed for production, a different package is used instead.

References

• https://github.com/JacksonGL/NPM-Vuln-PoC/blob/master/directory-traversal/yjmyjmyjm
• https://www.npmjs.com/advisories/451