{"containers": {"cna": {"affected": [{"product": "n/a", "vendor": "n/a", "versions": [{"status": "affected", "version": "n/a"}]}], "descriptions": [{"lang": "en", "value": "AuthRestServlet in Matrix Synapse before 1.21.0 is vulnerable to XSS due to unsafe interpolation of the session GET parameter. This allows a remote attacker to execute an XSS attack on the domain Synapse is hosted on, by supplying the victim user with a malicious URL to the /_matrix/client/r0/auth/*/fallback/web or /_matrix/client/unstable/auth/*/fallback/web Synapse endpoints."}], "problemTypes": [{"descriptions": [{"description": "n/a", "lang": "en", "type": "text"}]}], "providerMetadata": {"dateUpdated": "2020-10-20T20:05:41.000Z", "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "shortName": "mitre"}, "references": [{"tags": ["x_refsource_MISC"], "url": "https://github.com/matrix-org/synapse/pull/8444"}, {"tags": ["x_refsource_MISC"], "url": "https://matrix.org/blog/2020/10/15/synapse-1-21-2-released-and-security-advisory"}, {"tags": ["x_refsource_MISC"], "url": "https://github.com/matrix-org/synapse/releases/tag/v1.21.2"}, {"tags": ["x_refsource_CONFIRM"], "url": "https://github.com/matrix-org/synapse/security/advisories/GHSA-3x8c-fmpc-5rmq"}], "x_legacyV4Record": {"CVE_data_meta": {"ASSIGNER": "cve@mitre.org", "ID": "CVE-2020-26891", "STATE": "PUBLIC"}, "affects": {"vendor": {"vendor_data": [{"product": {"product_data": [{"product_name": "n/a", "version": {"version_data": [{"version_value": "n/a"}]}}]}, "vendor_name": "n/a"}]}}, "data_format": "MITRE", "data_type": "CVE", "data_version": "4.0", "description": {"description_data": [{"lang": "eng", "value": "AuthRestServlet in Matrix Synapse before 1.21.0 is vulnerable to XSS due to unsafe interpolation of the session GET parameter. This allows a remote attacker to execute an XSS attack on the domain Synapse is hosted on, by supplying the victim user with a malicious URL to the /_matrix/client/r0/auth/*/fallback/web or /_matrix/client/unstable/auth/*/fallback/web Synapse endpoints."}]}, "problemtype": {"problemtype_data": [{"description": [{"lang": "eng", "value": "n/a"}]}]}, "references": {"reference_data": [{"name": "https://github.com/matrix-org/synapse/pull/8444", "refsource": "MISC", "url": "https://github.com/matrix-org/synapse/pull/8444"}, {"name": "https://matrix.org/blog/2020/10/15/synapse-1-21-2-released-and-security-advisory", "refsource": "MISC", "url": "https://matrix.org/blog/2020/10/15/synapse-1-21-2-released-and-security-advisory"}, {"name": "https://github.com/matrix-org/synapse/releases/tag/v1.21.2", "refsource": "MISC", "url": "https://github.com/matrix-org/synapse/releases/tag/v1.21.2"}, {"name": "https://github.com/matrix-org/synapse/security/advisories/GHSA-3x8c-fmpc-5rmq", "refsource": "CONFIRM", "url": "https://github.com/matrix-org/synapse/security/advisories/GHSA-3x8c-fmpc-5rmq"}]}}}, "adp": [{"providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-04T16:03:22.630Z"}, "title": "CVE Program Container", "references": [{"tags": ["x_refsource_MISC", "x_transferred"], "url": "https://github.com/matrix-org/synapse/pull/8444"}, {"tags": ["x_refsource_MISC", "x_transferred"], "url": "https://matrix.org/blog/2020/10/15/synapse-1-21-2-released-and-security-advisory"}, {"tags": ["x_refsource_MISC", "x_transferred"], "url": "https://github.com/matrix-org/synapse/releases/tag/v1.21.2"}, {"tags": ["x_refsource_CONFIRM", "x_transferred"], "url": "https://github.com/matrix-org/synapse/security/advisories/GHSA-3x8c-fmpc-5rmq"}]}]}, "cveMetadata": {"assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "assignerShortName": "mitre", "cveId": "CVE-2020-26891", "datePublished": "2020-10-19T16:47:17.000Z", "dateReserved": "2020-10-08T00:00:00.000Z", "dateUpdated": "2024-08-04T16:03:22.630Z", "state": "PUBLISHED"}, "dataType": "CVE_RECORD", "dataVersion": "5.1"}

{}

{"affected": [{"affectedData": [{"product": "n/a", "vendor": "n/a", "versions": [{"status": "affected", "version": "n/a"}]}], "source": "cve@mitre.org"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:*", "matchCriteriaId": "39E3BC16-D440-463F-BC7B-B640865B60B4", "versionEndExcluding": "1.21.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "AuthRestServlet in Matrix Synapse before 1.21.0 is vulnerable to XSS due to unsafe interpolation of the session GET parameter. This allows a remote attacker to execute an XSS attack on the domain Synapse is hosted on, by supplying the victim user with a malicious URL to the /_matrix/client/r0/auth/*/fallback/web or /_matrix/client/unstable/auth/*/fallback/web Synapse endpoints."}, {"lang": "es", "value": "AuthRestServlet en Matrix Synapse versiones anteriores a 1.21.0 es vulnerable a XSS debido a la interpolaci\u00f3n insegura del par\u00e1metro GET de la sesi\u00f3n. Esto permite a un atacante remoto ejecutar un ataque XSS en el dominio en el que est\u00e1 alojado Synapse, suministrando al usuario v\u00edctima una URL maliciosa a los puntos finales de /_matrix/cliente/r0/auth/*/fallback/web o /_matrix/cliente/instable/auth/*/fallback/web Synapse"}], "id": "CVE-2020-26891", "lastModified": "2026-06-17T03:08:28.523", "metrics": {"cvssMetricV2": [{"acInsufInfo": false, "baseSeverity": "MEDIUM", "cvssData": {"accessComplexity": "MEDIUM", "accessVector": "NETWORK", "authentication": "NONE", "availabilityImpact": "NONE", "baseScore": 4.3, "confidentialityImpact": "NONE", "integrityImpact": "PARTIAL", "vectorString": "AV:N/AC:M/Au:N/C:N/I:P/A:N", "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": "NONE", "baseScore": 6.1, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 2.7, "source": "nvd@nist.gov", "type": "Primary"}]}, "published": "2020-10-19T17:15:13.220", "references": [{"source": "cve@mitre.org", "tags": ["Issue Tracking", "Patch", "Third Party Advisory"], "url": "https://github.com/matrix-org/synapse/pull/8444"}, {"source": "cve@mitre.org", "tags": ["Release Notes", "Third Party Advisory"], "url": "https://github.com/matrix-org/synapse/releases/tag/v1.21.2"}, {"source": "cve@mitre.org", "tags": ["Patch", "Third Party Advisory"], "url": "https://github.com/matrix-org/synapse/security/advisories/GHSA-3x8c-fmpc-5rmq"}, {"source": "cve@mitre.org", "tags": ["Release Notes", "Vendor Advisory"], "url": "https://matrix.org/blog/2020/10/15/synapse-1-21-2-released-and-security-advisory"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Issue Tracking", "Patch", "Third Party Advisory"], "url": "https://github.com/matrix-org/synapse/pull/8444"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Release Notes", "Third Party Advisory"], "url": "https://github.com/matrix-org/synapse/releases/tag/v1.21.2"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch", "Third Party Advisory"], "url": "https://github.com/matrix-org/synapse/security/advisories/GHSA-3x8c-fmpc-5rmq"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Release Notes", "Vendor Advisory"], "url": "https://matrix.org/blog/2020/10/15/synapse-1-21-2-released-and-security-advisory"}], "sourceIdentifier": "cve@mitre.org", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-79"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{}

{}