{"api_version":"1","generated_at":"2026-08-12T02:25:39+00:00","cve":"CVE-2026-72916","urls":{"html":"https://cve.report/CVE-2026-72916","api":"https://cve.report/api/cve/CVE-2026-72916.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-72916","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-72916"},"summary":{"title":"Mastodon: SSRF Protection Bypass via IPv4-compatible IPv6 Addresses","description":"Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.4.21, 4.5.14, 4.6.4, and 4.7.0-beta.1, PrivateAddressCheck.private_address? in app/lib/private_address_check.rb normalized IPv4-mapped IPv6 addresses but did not recognize IPv4-compatible IPv6 addresses with IPAddr#ipv4_compat?. An attacker could supply an address in the omitted range to bypass the ALLOWED_PRIVATE_ADDRESSES protection and make Mastodon send HTTP requests to loopback interfaces, potentially accessing private resources and services. Exploitation requires a system that supports the obsolete IPv4-compatible IPv6 mechanism. This issue is fixed in versions 4.4.21, 4.5.14, 4.6.4, and 4.7.0-beta.1.","state":"PUBLISHED","assigner":"GitHub_M","published_at":"2026-08-10 22:17:10","updated_at":"2026-08-10 22:17:10"},"problem_types":["CWE-918","CWE-1286","CWE-918 CWE-918: Server-Side Request Forgery (SSRF)","CWE-1286 CWE-1286: Improper Validation of Syntactic Correctness of 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Prior to 4.4.21, 4.5.14, 4.6.4, and 4.7.0-beta.1, PrivateAddressCheck.private_address? in app/lib/private_address_check.rb normalized IPv4-mapped IPv6 addresses but did not recognize IPv4-compatible IPv6 addresses with IPAddr#ipv4_compat?. An attacker could supply an address in the omitted range to bypass the ALLOWED_PRIVATE_ADDRESSES protection and make Mastodon send HTTP requests to loopback interfaces, potentially accessing private resources and services. Exploitation requires a system that supports the obsolete IPv4-compatible IPv6 mechanism. This issue is fixed in versions 4.4.21, 4.5.14, 4.6.4, and 4.7.0-beta.1."}],"metrics":[{"cvssV4_0":{"attackComplexity":"HIGH","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":6.3,"baseSeverity":"MEDIUM","privilegesRequired":"NONE","subAvailabilityImpact":"LOW","subConfidentialityImpact":"LOW","subIntegrityImpact":"LOW","userInteraction":"NONE","vectorString":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:L","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-918","description":"CWE-918: Server-Side Request Forgery (SSRF)","lang":"en","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-1286","description":"CWE-1286: Improper Validation of Syntactic Correctness of 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Prior to 4.4.21, 4.5.14, 4.6.4, and 4.7.0-beta.1, PrivateAddressCheck.private_address? in app/lib/private_address_check.rb normalized IPv4-mapped IPv6 addresses but did not recognize IPv4-compatible IPv6 addresses with IPAddr#ipv4_compat?. An attacker could supply an address in the omitted range to bypass the ALLOWED_PRIVATE_ADDRESSES protection and make Mastodon send HTTP requests to loopback interfaces, potentially accessing private resources and services. Exploitation requires a system that supports the obsolete IPv4-compatible IPv6 mechanism. This issue is fixed in versions 4.4.21, 4.5.14, 4.6.4, and 4.7.0-beta.1.","Type":"Description","Title":"Mastodon: SSRF Protection Bypass via IPv4-compatible IPv6 Addres"}]}}}