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.
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History
Mon, 15 Dec 2025 23:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | Misskey has a login rate limit bypass via spoofed X-Forwarded-For header | |
| Weaknesses | CWE-1188 CWE-307 |
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cvssV4_0
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2025-12-15T23:18:53.415Z
Reserved: 2025-12-02T17:09:52.016Z
Link: CVE-2025-66482
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Status : Received
Published: 2025-12-16T00:16:02.503
Modified: 2025-12-16T00:16:02.503
Link: CVE-2025-66482
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OpenCVE Enrichment
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