{"id":"CVE-2025-66482","state":"PUBLISHED","title":"Misskey has a login rate limit bypass via spoofed X-Forwarded-For header","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.","publishedAt":"2025-12-15T23:18:37.295Z","updatedAt":"2025-12-16T15:09:19.925Z","severity":{"score":6.9,"label":"Medium","version":"4.0","vector":"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","source":"GitHub_M"},"assigner":"GitHub_M","products":["misskey-dev misskey"],"affected":[{"vendor":"misskey-dev","product":"misskey","versions":[{"version":">= 2025.9.1, < 2025.12.0-alpha.2","status":"affected"}]}],"references":["https://github.com/misskey-dev/misskey/security/advisories/GHSA-wwrj-3hvj-prpm","https://github.com/misskey-dev/misskey/commit/5512898463fa8487b9e6488912f35102b91f25f7"],"weaknesses":["CWE-307","CWE-1188"],"ingestedAt":"2026-10-29T20:09:56.034Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/66xxx/CVE-2025-66482.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-66482","state":"PUBLISHED","datePublished":"2025-12-15T23:18:37.295Z","dateUpdated":"2025-12-16T15:09:19.925Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2025-12-02T17:09:52.016Z"},"containers":{"cna":{"title":"Misskey has a login rate limit bypass via spoofed X-Forwarded-For header","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"misskey-dev","product":"misskey","versions":[{"version":">= 2025.9.1, < 2025.12.0-alpha.2","status":"affected"}]}],"references":[{"url":"https://github.com/misskey-dev/misskey/security/advisories/GHSA-wwrj-3hvj-prpm","name":"https://github.com/misskey-dev/misskey/security/advisories/GHSA-wwrj-3hvj-prpm","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/misskey-dev/misskey/commit/5512898463fa8487b9e6488912f35102b91f25f7","name":"https://github.com/misskey-dev/misskey/commit/5512898463fa8487b9e6488912f35102b91f25f7","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","vulnAvailabilityImpact":"LOW","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6.9,"baseSeverity":"MEDIUM","vectorString":"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","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-307","lang":"en","description":"CWE-307: Improper Restriction of Excessive Authentication Attempts","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-1188","lang":"en","description":"CWE-1188: Insecure Default Initialization of Resource","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2025-12-15T23:18:53.415Z"},"source":{"advisory":"GHSA-wwrj-3hvj-prpm","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/misskey-dev/misskey/security/advisories/GHSA-wwrj-3hvj-prpm","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2025-12-16T14:37:27.348528Z","id":"CVE-2025-66482","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2025-12-16T15:09:19.925Z"}}]}}}