GHSA-wwrj-3hvj-prpm

Source

https://github.com/advisories/GHSA-wwrj-3hvj-prpm

Import Source

https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/12/GHSA-wwrj-3hvj-prpm/GHSA-wwrj-3hvj-prpm.json

JSON Data

https://api.osv.dev/v1/vulns/GHSA-wwrj-3hvj-prpm

Aliases

CVE-2025-66482

Published

2025-12-15T20:59:59Z

Modified

2026-02-03T03:16:38Z

Severity

6.5 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L CVSS Calculator
6.9 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N CVSS Calculator

Summary

Misskey has a login rate limit bypass via spoofed X-Forwarded-For header

Details

Summary

When using an untrusted reverse proxy or not using a reverse proxy at all, attackers can bypass IP rate limiting by adding a forged X-Forwarded-For header. Starting with version 2025.9.1, an option (trustProxy) has been added in config file to prevent this from happening. However, it is initialized with an insecure default value before version 2025.12.0, making it still vulnerable if the configuration is not set correctly.

Workaround

If you are running Misskey with a trusted reverse proxy, you should not be affected by this vulnerability.

There is no workaround for the Misskey itself. Please update Misskey to the latest version or set up a trusted reverse proxy.
From v2025.9.1 to v2025.11.1, workaround is available. Set trustProxy: false in config file.
This is patched in v2025.12.0 by flipping default value of trustProxy to false. If you are using trusted reverse proxy and not remember you manually overrided this value, please take time to check your config for optimal behavior.

Details

Fastify recommend not trusting X-Forwarded-For IPs Due to misconfiguration in https://github.com/misskey-dev/misskey/blob/develop/packages/backend/src/server/api/SigninApiService.ts#L94 attacks can spoof their IPs.

PoC

POST /api/signin-flow HTTP/1.1
Host: misskey.localhost:3123
Content-Length: 45
Content-Type: application/json
Connection: keep-alive
X-Forwarded-For: 127.1.1.31, 1.1.1.12

{"username":"admin",
	"password":"password"}

Impact

An attacker can brute force accounts bypassing rate limiting protection.

Database specific

{
    "cwe_ids":  [
        "CWE-1188",
        "CWE-307"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2025-12-15T20:59:59Z",
    "nvd_published_at":  "2025-12-16T00:16:02Z",
    "severity":  "MODERATE"
}

References

Affected packages

npm / misskey-js

Package

Name: misskey-js; View open source insights on deps.dev
Purl: pkg:npm/misskey-js

Affected ranges

Type: SEMVER
Events: Introduced

2025.9.1

Fixed

2025.12.0-alpha.2

Database specific

source

"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/12/GHSA-wwrj-3hvj-prpm/GHSA-wwrj-3hvj-prpm.json"