CVE-2025-66482 Misskey has a login rate limit bypass via spoofed X-Forwarded-For header
Attackers can bypass IP rate limiting by spoofing the X-Forwarded-For header when using an untrusted reverse proxy or no proxy.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-66482?
CVE-2025-66482 is a medium-severity vulnerability in misskey-dev misskey, published on 15 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Misskey is an open source, federated social media platform. Attackers who use an untrusted reverse proxy or not using a reverse proxy at all 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-alpha.2, making it still vulnerable if the configuration is not set correctly. This is patched in v2025.12.0-alpha.2 by flipping default value of `trustProxy` to `false`. Users of a trusted reverse proxy who are unsure if they manually overode this value should check their config for optimal behavior. Users are running Misskey with a trusted reverse proxy should not be affected by this vulnerability. From v2025.9.1 to v2025.11.1, workaround is available. Set `trustProxy: false` in config file.
Which versions are affected by CVE-2025-66482?
2 open source packages ship an affected version, including misskey-js. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
misskey-js npm | From 2025.9.1 | 2025.12.0-alpha.2 |
misskey-js npm | From 2025.9.1 | 2025.12.0-alpha.2 |
Products include Misskey Misskey.
How do I fix CVE-2025-66482?
Upgrade misskey-js to 2025.12.0-alpha.2 or later.
Is CVE-2025-66482 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-66482 exists.
Other vulnerabilities in misskey-dev misskey
- CVE-2025-25306 Misskey's Incomplete Patch of CVE-2024-52591 Leads to Forgery of Federated Notes
- CVE-2023-49079 Misskey's missing signature validation allows arbitrary users to impersonate any remote user.
- CVE-2026-28431 Misskey lacks proper authorization checks and input validation
- CVE-2023-52139 Misskey vulnerable to improper authorization when accessing with third-party application
- CVE-2024-52590 Missing validation allows spoofed profiles in Misskey
Sources
Also known as GHSA-wwrj-3hvj-prpm.