CVE-2020-26891

{"cve": {"data_type": "CVE", "references": {"reference_data": [{"url": "https://matrix.org/blog/2020/10/15/synapse-1-21-2-released-and-security-advisory", "name": "https://matrix.org/blog/2020/10/15/synapse-1-21-2-released-and-security-advisory", "tags": ["Release Notes", "Vendor Advisory"], "refsource": "MISC"}, {"url": "https://github.com/matrix-org/synapse/pull/8444", "name": "https://github.com/matrix-org/synapse/pull/8444", "tags": ["Issue Tracking", "Patch", "Third Party Advisory"], "refsource": "MISC"}, {"url": "https://github.com/matrix-org/synapse/releases/tag/v1.21.2", "name": "https://github.com/matrix-org/synapse/releases/tag/v1.21.2", "tags": ["Release Notes", "Third Party Advisory"], "refsource": "MISC"}, {"url": "https://github.com/matrix-org/synapse/security/advisories/GHSA-3x8c-fmpc-5rmq", "name": "https://github.com/matrix-org/synapse/security/advisories/GHSA-3x8c-fmpc-5rmq", "tags": ["Patch", "Third Party Advisory"], "refsource": "CONFIRM"}]}, "data_format": "MITRE", "description": {"description_data": [{"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."}]}, "problemtype": {"problemtype_data": [{"description": [{"lang": "en", "value": "CWE-79"}]}]}, "data_version": "4.0", "CVE_data_meta": {"ID": "CVE-2020-26891", "ASSIGNER": "cve@mitre.org"}}, "impact": {"baseMetricV2": {"cvssV2": {"version": "2.0", "baseScore": 4.3, "accessVector": "NETWORK", "vectorString": "AV:N/AC:M/Au:N/C:N/I:P/A:N", "authentication": "NONE", "integrityImpact": "PARTIAL", "accessComplexity": "MEDIUM", "availabilityImpact": "NONE", "confidentialityImpact": "NONE"}, "severity": "MEDIUM", "acInsufInfo": false, "impactScore": 2.9, "obtainAllPrivilege": false, "exploitabilityScore": 8.6, "obtainUserPrivilege": false, "obtainOtherPrivilege": false, "userInteractionRequired": true}, "baseMetricV3": {"cvssV3": {"scope": "CHANGED", "version": "3.1", "baseScore": 6.1, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "REQUIRED", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "LOW"}, "impactScore": 2.7, "exploitabilityScore": 2.8}}, "publishedDate": "2020-10-19T17:15Z", "configurations": {"nodes": [{"children": [], "operator": "OR", "cpe_match": [{"cpe23Uri": "cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true, "versionEndExcluding": "1.21.0"}]}], "CVE_data_version": "4.0"}, "lastModifiedDate": "2020-10-26T21:30Z"}