Open Redirect in Fastify Fastify-Static

CVE-2021-22963

A redirect vulnerability in the fastify-static module version < 4.2.4 allows remote attackers to redirect 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.

Vulnerability class: Open Redirect

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.012 (67.1th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 67th percentile — 67.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2021-22963: held from 0.012 to 0.012.

EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: 0.000

Affected products

  • Fastify Fastify-Static
  • Https://github.com/fastify/fastify-Static — versions Affects < v4.2.4. Fixed in >= v4.2.4

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2021-22963?
CVE-2021-22963 is a medium-severity vulnerability in Fastify Fastify-Static, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 6.1/10. Published 2021-10-14.
How severe is CVE-2021-22963?
Medium severity. CVSS v3 base score is 6.1 out of 10.
Is CVE-2021-22963 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.