PenDoc vulnerable to Arbitrary File Read on updating and downloading templates using Path Traversal

Vulnerability Description

PwnDoc is a penetration test report generator. Prior to commit 1d4219c596f4f518798492e48386a20c6e9a2fe6, an authenticated user who is able to update and download templates can inject path traversal (`../`) sequences into the file extension property to read arbitrary files on the system. Commit 1d4219c596f4f518798492e48386a20c6e9a2fe6 contains a patch for the issue.

References

• https://github.com/pwndoc/pwndoc/security/advisories/GHSA-2mqc-gg7h-76p6
• https://github.com/pwndoc/pwndoc/commit/1d4219c596f4f518798492e48386a20c6e9a2fe6
• https://gist.github.com/JorianWoltjer/8a42e25c6dfa7604020d2a226e193407
• https://github.com/pwndoc/pwndoc/blob/2e7f5747d5688b1368e549c786ce7266fe5ab2b5/backend/src/routes/template.js#L103
• https://github.com/pwndoc/pwndoc/blob/2e7f5747d5688b1368e549c786ce7266fe5ab2b5/backend/src/routes/template.js#L43-L47