CVE-2021-22963
URL Redirection to Untrusted Site ('Open Redirect') in fastify-static
Description
### Impact A redirect vulnerability in the `fastify-static` module allows remote attackers to redirect Mozilla Firefox users to arbitrary websites via a double slash `//` followed by a domain: `http://localhost:3000//google.com/%2e%2e`. The issue shows up on all the `fastify-static` applications that set `redirect: true` option. By default, it is `false`. ### Patches The issue has been patched in `fastify-static@4.2.4` ### Workarounds If updating is not an option, you can sanitize the input URLs using the [`rewriteUrl`](https://www.fastify.io/docs/latest/Server/#rewriteurl) server option. ### References + Bug founder: drstrnegth + [hackerone Report](https://hackerone.com/reports/1354255) ### For more information If you have any questions or comments about this advisory: * Open an issue in [fastify-static](https://github.com/fastify/fastify-static) * Contact the [security team](https://github.com/fastify/fastify/blob/main/SECURITY.md#the-fastify-security-team)
How to fix CVE-2021-22963
To remediate CVE-2021-22963, upgrade the affected package to a fixed version below.
- —upgrade to 4.2.4 or later
Is CVE-2021-22963 being exploited?
Low — EPSS is 0.2%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 4.2.4
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |