GHSA-qmw8-3v4g-gwj4

### Impact

By crafting a specific URL, it is possible to escape the prefix of the proxied backend service. If the base url of the proxied server is `/pub/`, a user expect that accessing `/priv` on the target service would not be possible. Unfortunately, it is.

[CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N](https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N)

### Patches

A patch have been submitted by Corey Farrell git@cfware.com, the reporter. All releases after v4.0.2 include the fix.

### Workarounds

There are no workaround available.

### For more information If you have any questions or comments about this advisory: * Open an issue in [fastify-reply-from](https://github.com/fastify/fastify-reply-from) * Email us at [hello@matteocollina.com](mailto:hello@matteocollina.com)