CVE-2021-21322
Prefix escape
Description
### 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 All releases after v4.3.1 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 [[email protected]](mailto:[email protected])
How to fix CVE-2021-21322
To remediate CVE-2021-21322, upgrade the affected package to a fixed version below.
- —upgrade to 4.3.1 or later
Is CVE-2021-21322 being exploited?
Low — EPSS is 0.2%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 4.3.1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | CRITICAL10.0 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N |