CVE-2021-21274

{"containers": {"cna": {"affected": [{"product": "synapse", "vendor": "matrix-org", "versions": [{"status": "affected", "version": ">=0.99.0, < 1.25.0"}]}], "descriptions": [{"lang": "en", "value": "Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an ecosystem for open federated Instant Messaging and VoIP. In Synapse before version 1.25.0, a malicious homeserver could redirect requests to their .well-known file to a large file. This can lead to a denial of service attack where homeservers will consume significantly more resources when requesting the .well-known file of a malicious homeserver. This affects any server which accepts federation requests from untrusted servers. Issue is resolved in version 1.25.0. As a workaround the `federation_domain_whitelist` setting can be used to restrict the homeservers communicated with over federation."}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 4.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L", "version": "3.1"}}], "problemTypes": [{"descriptions": [{"cweId": "CWE-400", "description": "CWE-400 Uncontrolled Resource Consumption", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"dateUpdated": "2021-08-02T02:06:23.000Z", "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M"}, "references": [{"tags": ["x_refsource_CONFIRM"], "url": "https://github.com/matrix-org/synapse/security/advisories/GHSA-2hwx-mjrm-v3g8"}, {"tags": ["x_refsource_MISC"], "url": "https://github.com/matrix-org/synapse/releases/tag/v1.25.0"}, {"tags": ["x_refsource_MISC"], "url": "https://github.com/matrix-org/synapse/pull/8950"}, {"tags": ["x_refsource_MISC"], "url": "https://github.com/matrix-org/synapse/commit/ff5c4da1289cb5e097902b3e55b771be342c29d6"}, {"name": "FEDORA-2021-a627cfd31e", "tags": ["vendor-advisory", "x_refsource_FEDORA"], "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/"}], "source": {"advisory": "GHSA-2hwx-mjrm-v3g8", "discovery": "UNKNOWN"}, "title": "Denial of service attack via .well-known lookups", "x_legacyV4Record": {"CVE_data_meta": {"ASSIGNER": "security-advisories@github.com", "ID": "CVE-2021-21274", "STATE": "PUBLIC", "TITLE": "Denial of service attack via .well-known lookups"}, "affects": {"vendor": {"vendor_data": [{"product": {"product_data": [{"product_name": "synapse", "version": {"version_data": [{"version_value": ">=0.99.0, < 1.25.0"}]}}]}, "vendor_name": "matrix-org"}]}}, "data_format": "MITRE", "data_type": "CVE", "data_version": "4.0", "description": {"description_data": [{"lang": "eng", "value": "Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an ecosystem for open federated Instant Messaging and VoIP. In Synapse before version 1.25.0, a malicious homeserver could redirect requests to their .well-known file to a large file. This can lead to a denial of service attack where homeservers will consume significantly more resources when requesting the .well-known file of a malicious homeserver. This affects any server which accepts federation requests from untrusted servers. Issue is resolved in version 1.25.0. As a workaround the `federation_domain_whitelist` setting can be used to restrict the homeservers communicated with over federation."}]}, "impact": {"cvss": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 4.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L", "version": "3.1"}}, "problemtype": {"problemtype_data": [{"description": [{"lang": "eng", "value": "CWE-400 Uncontrolled Resource Consumption"}]}]}, "references": {"reference_data": [{"name": "https://github.com/matrix-org/synapse/security/advisories/GHSA-2hwx-mjrm-v3g8", "refsource": "CONFIRM", "url": "https://github.com/matrix-org/synapse/security/advisories/GHSA-2hwx-mjrm-v3g8"}, {"name": "https://github.com/matrix-org/synapse/releases/tag/v1.25.0", "refsource": "MISC", "url": "https://github.com/matrix-org/synapse/releases/tag/v1.25.0"}, {"name": "https://github.com/matrix-org/synapse/pull/8950", "refsource": "MISC", "url": "https://github.com/matrix-org/synapse/pull/8950"}, {"name": "https://github.com/matrix-org/synapse/commit/ff5c4da1289cb5e097902b3e55b771be342c29d6", "refsource": "MISC", "url": "https://github.com/matrix-org/synapse/commit/ff5c4da1289cb5e097902b3e55b771be342c29d6"}, {"name": "FEDORA-2021-a627cfd31e", "refsource": "FEDORA", "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/"}]}, "source": {"advisory": "GHSA-2hwx-mjrm-v3g8", "discovery": "UNKNOWN"}}}, "adp": [{"providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-03T18:09:15.070Z"}, "title": "CVE Program Container", "references": [{"tags": ["x_refsource_CONFIRM", "x_transferred"], "url": "https://github.com/matrix-org/synapse/security/advisories/GHSA-2hwx-mjrm-v3g8"}, {"tags": ["x_refsource_MISC", "x_transferred"], "url": "https://github.com/matrix-org/synapse/releases/tag/v1.25.0"}, {"tags": ["x_refsource_MISC", "x_transferred"], "url": "https://github.com/matrix-org/synapse/pull/8950"}, {"tags": ["x_refsource_MISC", "x_transferred"], "url": "https://github.com/matrix-org/synapse/commit/ff5c4da1289cb5e097902b3e55b771be342c29d6"}, {"name": "FEDORA-2021-a627cfd31e", "tags": ["vendor-advisory", "x_refsource_FEDORA", "x_transferred"], "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/"}]}]}, "cveMetadata": {"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "assignerShortName": "GitHub_M", "cveId": "CVE-2021-21274", "datePublished": "2021-02-26T17:25:16.000Z", "dateReserved": "2020-12-22T00:00:00.000Z", "dateUpdated": "2024-08-03T18:09:15.070Z", "state": "PUBLISHED"}, "dataType": "CVE_RECORD", "dataVersion": "5.1"}

{}

{"affected": [{"affectedData": [{"product": "synapse", "vendor": "matrix-org", "versions": [{"status": "affected", "version": ">=0.99.0, < 1.25.0"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:*", "matchCriteriaId": "6C16EE11-380E-400F-9A55-6068AAF132D8", "versionEndExcluding": "1.25.0", "versionStartIncluding": "0.99.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}, {"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*", "matchCriteriaId": "A930E247-0B43-43CB-98FF-6CE7B8189835", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an ecosystem for open federated Instant Messaging and VoIP. In Synapse before version 1.25.0, a malicious homeserver could redirect requests to their .well-known file to a large file. This can lead to a denial of service attack where homeservers will consume significantly more resources when requesting the .well-known file of a malicious homeserver. This affects any server which accepts federation requests from untrusted servers. Issue is resolved in version 1.25.0. As a workaround the `federation_domain_whitelist` setting can be used to restrict the homeservers communicated with over federation."}, {"lang": "es", "value": "Synapse es un servidor dom\u00e9stico de referencia de Matrix escrito en python (paquete pypi matrix-synapse).&#xa0;Matrix es un ecosistema para VoIP y mensajer\u00eda instant\u00e1nea federada abierta.&#xa0;En Synapse versiones anteriores a 1.25.0, un servidor dom\u00e9stico malicioso pod\u00eda redireccionar las peticiones para su archivo .well-known a un archivo grande.&#xa0;Esto puede conllevar a un ataque de denegaci\u00f3n de servicio en el que los servidores dom\u00e9sticos consumir\u00e1n significativamente m\u00e1s recursos al solicitar el archivo .well-known de un servidor dom\u00e9stico malicioso.&#xa0;Esto afecta a cualquier servidor que acepte peticiones de federaci\u00f3n desde servidores que no sean confiables.&#xa0;El problema es resuelto en versi\u00f3n 1.25.0.&#xa0;Como soluci\u00f3n alternativa, el ajuste de \"federation_domain_whitelist\" puede ser usado para restringir los servidores dom\u00e9sticos que se comunican con la federaci\u00f3n"}], "id": "CVE-2021-21274", "lastModified": "2026-06-17T03:35:10.330", "metrics": {"cvssMetricV2": [{"acInsufInfo": false, "baseSeverity": "MEDIUM", "cvssData": {"accessComplexity": "MEDIUM", "accessVector": "NETWORK", "authentication": "NONE", "availabilityImpact": "PARTIAL", "baseScore": 4.3, "confidentialityImpact": "NONE", "integrityImpact": "NONE", "vectorString": "AV:N/AC:M/Au:N/C:N/I:N/A:P", "version": "2.0"}, "exploitabilityScore": 8.6, "impactScore": 2.9, "obtainAllPrivilege": false, "obtainOtherPrivilege": false, "obtainUserPrivilege": false, "source": "nvd@nist.gov", "type": "Primary", "userInteractionRequired": true}], "cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 4.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 1.4, "source": "security-advisories@github.com", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}]}, "published": "2021-02-26T18:15:12.237", "references": [{"source": "security-advisories@github.com", "tags": ["Patch", "Third Party Advisory"], "url": "https://github.com/matrix-org/synapse/commit/ff5c4da1289cb5e097902b3e55b771be342c29d6"}, {"source": "security-advisories@github.com", "tags": ["Patch", "Third Party Advisory"], "url": "https://github.com/matrix-org/synapse/pull/8950"}, {"source": "security-advisories@github.com", "tags": ["Third Party Advisory"], "url": "https://github.com/matrix-org/synapse/releases/tag/v1.25.0"}, {"source": "security-advisories@github.com", "tags": ["Patch", "Third Party Advisory"], "url": "https://github.com/matrix-org/synapse/security/advisories/GHSA-2hwx-mjrm-v3g8"}, {"source": "security-advisories@github.com", "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch", "Third Party Advisory"], "url": "https://github.com/matrix-org/synapse/commit/ff5c4da1289cb5e097902b3e55b771be342c29d6"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch", "Third Party Advisory"], "url": "https://github.com/matrix-org/synapse/pull/8950"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Third Party Advisory"], "url": "https://github.com/matrix-org/synapse/releases/tag/v1.25.0"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch", "Third Party Advisory"], "url": "https://github.com/matrix-org/synapse/security/advisories/GHSA-2hwx-mjrm-v3g8"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-400"}], "source": "security-advisories@github.com", "type": "Secondary"}, {"description": [{"lang": "en", "value": "CWE-770"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{}

{}