CVE-2021-22964

Exp

A redirect vulnerability in the `fastify-static` module version >= 4.2.4 and < 4.4.1 allows remote attackers to redirect Mozilla Firefox users to arbitrary websites via a double slash `//` followed by a domain: `http://localhost:3000//a//youtube.com/%2e%2e%2f%2e%2e`.A DOS vulnerability is possible if the URL contains invalid characters `curl --path-as-is "http://localhost:3000//^/.."`The issue shows up on all the `fastify-static` applications that set `redirect: true` option. By default, it is `false`.

Published: 2021-10-14 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-22964 is rated High Exploit Risk (71/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.99%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-22964

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-22964

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.36% 0.99% +0.63%
2 2026-03-04 0.31% 0.36% +0.05%
3 2026-03-01 — 0.31% —

Full EPSS history (33 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-22964

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.3 [email protected]
6.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 6.4 [email protected]

Weakness enumeration for CVE-2021-22964

GitHub Security Advisory for CVE-2021-22964

GHSA-pgh6-m65r-2rhq · Severity: high · Ecosystem: npm — DOS and Open Redirect with user input

OS Trackers for CVE-2021-22964

vendor priority summary link
redhat medium — https://access.redhat.com/security/cve/CVE-2021-22964

Affected software / configurations for CVE-2021-22964

Vendor Product Version Raw CPE
fastify fastify-static >= 4.2.4, < 4.4.1 cpe:2.3:a:fastify:fastify-static:*:*:*:*:*:*:*:*

References for CVE-2021-22964

URL Tags
https://hackerone.com/reports/1361804 Exploit Issue Tracking Patch Third Party Advisory
cvelogic Threat Intelligence