{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-72916", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-08-10T17:57:26.143Z", "datePublished": "2026-08-10T21:19:02.908Z", "dateUpdated": "2026-08-10T21:19:02.908Z"}, "containers": {"cna": {"title": "Mastodon: SSRF Protection Bypass via IPv4-compatible IPv6 Addresses", "problemTypes": [{"descriptions": [{"cweId": "CWE-918", "lang": "en", "description": "CWE-918: Server-Side Request Forgery (SSRF)", "type": "CWE"}]}, {"descriptions": [{"cweId": "CWE-1286", "lang": "en", "description": "CWE-1286: Improper Validation of Syntactic Correctness of Input", "type": "CWE"}]}], "metrics": [{"cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "LOW", "subIntegrityImpact": "LOW", "subAvailabilityImpact": "LOW", "baseScore": 6.3, "baseSeverity": "MEDIUM", "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"}}], "references": [{"name": "https://github.com/mastodon/mastodon/security/advisories/GHSA-vwhj-3g83-v276", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/mastodon/mastodon/security/advisories/GHSA-vwhj-3g83-v276"}, {"name": "https://github.com/mastodon/mastodon/commit/18c61f286f1f5718a8f517940ba384866ffa3892", "tags": ["x_refsource_MISC"], "url": "https://github.com/mastodon/mastodon/commit/18c61f286f1f5718a8f517940ba384866ffa3892"}, {"name": "https://github.com/mastodon/mastodon/commit/467c933459c7d0e5513475b9e4888afaedfb1074", "tags": ["x_refsource_MISC"], "url": "https://github.com/mastodon/mastodon/commit/467c933459c7d0e5513475b9e4888afaedfb1074"}, {"name": "https://github.com/mastodon/mastodon/commit/930aa9fee26bf9eaefe27826fa1061288d83373b", "tags": ["x_refsource_MISC"], "url": "https://github.com/mastodon/mastodon/commit/930aa9fee26bf9eaefe27826fa1061288d83373b"}, {"name": "https://github.com/mastodon/mastodon/commit/da47a1bd3cd07935d7ca55a1f4f1a76f7f167e0d", "tags": ["x_refsource_MISC"], "url": "https://github.com/mastodon/mastodon/commit/da47a1bd3cd07935d7ca55a1f4f1a76f7f167e0d"}, {"name": "https://github.com/mastodon/mastodon/releases/tag/v4.4.21", "tags": ["x_refsource_MISC"], "url": "https://github.com/mastodon/mastodon/releases/tag/v4.4.21"}, {"name": "https://github.com/mastodon/mastodon/releases/tag/v4.5.14", "tags": ["x_refsource_MISC"], "url": "https://github.com/mastodon/mastodon/releases/tag/v4.5.14"}, {"name": "https://github.com/mastodon/mastodon/releases/tag/v4.6.4", "tags": ["x_refsource_MISC"], "url": "https://github.com/mastodon/mastodon/releases/tag/v4.6.4"}, {"name": "https://github.com/mastodon/mastodon/releases/tag/v4.7.0-beta.1", "tags": ["x_refsource_MISC"], "url": "https://github.com/mastodon/mastodon/releases/tag/v4.7.0-beta.1"}], "affected": [{"vendor": "mastodon", "product": "mastodon", "versions": [{"version": "< 4.4.21", "status": "affected"}, {"version": ">= 4.5.0-beta.1, < 4.5.14", "status": "affected"}, {"version": ">= 4.6.0-beta.1, < 4.6.4", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-08-10T21:19:02.908Z"}, "descriptions": [{"lang": "en", "value": "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."}], "source": {"advisory": "GHSA-vwhj-3g83-v276", "discovery": "UNKNOWN"}}}}

{}

{"affected": [{"affectedData": [{"product": "mastodon", "vendor": "mastodon", "versions": [{"status": "affected", "version": "< 4.4.21"}, {"status": "affected", "version": ">= 4.5.0-beta.1, < 4.5.14"}, {"status": "affected", "version": ">= 4.6.0-beta.1, < 4.6.4"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "id": "CVE-2026-72916", "lastModified": "2026-08-10T22:17:10.510", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 6.3, "baseSeverity": "MEDIUM", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "LOW", "subConfidentialityImpact": "LOW", "subIntegrityImpact": "LOW", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "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/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", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-08-10T22:17:10.510", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/mastodon/mastodon/commit/18c61f286f1f5718a8f517940ba384866ffa3892"}, {"source": "security-advisories@github.com", "url": "https://github.com/mastodon/mastodon/commit/467c933459c7d0e5513475b9e4888afaedfb1074"}, {"source": "security-advisories@github.com", "url": "https://github.com/mastodon/mastodon/commit/930aa9fee26bf9eaefe27826fa1061288d83373b"}, {"source": "security-advisories@github.com", "url": "https://github.com/mastodon/mastodon/commit/da47a1bd3cd07935d7ca55a1f4f1a76f7f167e0d"}, {"source": "security-advisories@github.com", "url": "https://github.com/mastodon/mastodon/releases/tag/v4.4.21"}, {"source": "security-advisories@github.com", "url": "https://github.com/mastodon/mastodon/releases/tag/v4.5.14"}, {"source": "security-advisories@github.com", "url": "https://github.com/mastodon/mastodon/releases/tag/v4.6.4"}, {"source": "security-advisories@github.com", "url": "https://github.com/mastodon/mastodon/releases/tag/v4.7.0-beta.1"}, {"source": "security-advisories@github.com", "url": "https://github.com/mastodon/mastodon/security/advisories/GHSA-vwhj-3g83-v276"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-918"}, {"lang": "en", "value": "CWE-1286"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,4.4.21)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[4.5.0-beta.1,4.5.14)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[4.6.0-beta.1,4.6.4)"}}], "enrichment": {"confidence": 89.0, "confidence_source": "matching", "scores": [{"score": 89.0, "source": "matching"}]}, "original": {"product": "mastodon", "source": "cna", "vendor": "mastodon"}, "product": "mastodon", "vendor": "joinmastodon"}], "created": "2026-08-10T22:45:05.166516+00:00", "updated": "2026-08-11T14:00:14.143241+00:00", "vendors": ["joinmastodon", "joinmastodon$PRODUCT$mastodon"]}