CVSS 3.1
10.0 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HCVE-2021-21321
Critical (10.0) in fastify-reply-from project fastify-reply-from. EPSS 1.8% chance of exploitation in the next 30 days. Fixed in fastify-reply-from 4.0.2.
fastify-reply-from is an npm package which is a fastify plugin to forward the current http request to another server. In fastify-reply-from before version 4.0.2, 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. In affected versions, it is possible. This is fixed in version 4.0.2.
Severity
- EPSS
- 1.8% chance of exploitation in the next 30 days; higher than 78% of CVEs (scores of 2026-10-31)
- CWE
- CWE-20
- Published
- Modified
- Record from
- the NVD, synced
Affected
- fastify-reply-from_project:fastify-reply-from
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-qmw8-3v4g-gwj4 | npm | fastify-reply-from | <4.0.2 | 4.0.2 |
References
- https://github.com/fastify/fastify-reply-from/commit/dea227dda606900cc01870d08541b4dcc69d3889
- https://github.com/fastify/fastify-reply-from/security/advisories/GHSA-qmw8-3v4g-gwj4
- https://www.npmjs.com/package/fastify-reply-from
- https://github.com/fastify/fastify-reply-from/commit/dea227dda606900cc01870d08541b4dcc69d3889
- https://github.com/fastify/fastify-reply-from/security/advisories/GHSA-qmw8-3v4g-gwj4