{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-74998", "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "state": "PUBLISHED", "assignerShortName": "mitre", "dateReserved": "2026-08-17T12:40:29.556Z", "datePublished": "2026-08-17T12:40:29.903Z", "dateUpdated": "2026-08-17T12:40:29.903Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "product": "Webmail", "vendor": "Roundcube", "versions": [{"lessThan": "1.6.18", "status": "affected", "version": "1.6.0", "versionType": "semver"}, {"lessThan": "1.7.3", "status": "affected", "version": "1.7.0", "versionType": "semver"}]}], "descriptions": [{"lang": "en", "value": "In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, responses from the CSS (Cascading Style Sheets) proxy were not validated, which may result in information disclosure or XSS (cross-site scripting) via MIME sniffing."}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.2, "baseSeverity": "HIGH", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N", "version": "3.1"}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"cweId": "CWE-79", "description": "CWE-79 Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting')", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "shortName": "mitre", "dateUpdated": "2026-08-17T12:40:29.903Z"}, "references": [{"url": "https://roundcube.net/news/2026/08/09/security-updates-1.6.18-and-1.7.3"}, {"url": "https://github.com/roundcube/roundcubemail/releases/tag/1.6.18"}, {"url": "https://github.com/roundcube/roundcubemail/commit/62d33c8a0dc3fd0dd03984220dc9709e8e0de43b"}, {"url": "https://github.com/roundcube/roundcubemail/releases/tag/1.7.3"}, {"url": "https://github.com/roundcube/roundcubemail/commit/a2334990c02f7cb77b1a8d6fa97fcd9e1b5cd1fb"}], "x_generator": {"engine": "CVE-Request-form 0.0.1"}, "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:roundcube:webmail:*:*:*:*:*:*:*:*", "versionStartIncluding": "1.6.0", "versionEndExcluding": "1.6.18"}, {"vulnerable": true, "criteria": "cpe:2.3:a:roundcube:webmail:*:*:*:*:*:*:*:*", "versionStartIncluding": "1.7.0", "versionEndExcluding": "1.7.3"}]}]}]}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Webmail", "vendor": "Roundcube", "versions": [{"lessThan": "1.6.18", "status": "affected", "version": "1.6.0", "versionType": "semver"}, {"lessThan": "1.7.3", "status": "affected", "version": "1.7.0", "versionType": "semver"}]}], "source": "cve@mitre.org"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, responses from the CSS (Cascading Style Sheets) proxy were not validated, which may result in information disclosure or XSS (cross-site scripting) via MIME sniffing."}], "id": "CVE-2026-74998", "lastModified": "2026-08-17T13:16:54.270", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.2, "baseSeverity": "HIGH", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 2.7, "source": "cve@mitre.org", "type": "Secondary"}]}, "published": "2026-08-17T13:16:54.270", "references": [{"source": "cve@mitre.org", "url": "https://github.com/roundcube/roundcubemail/commit/62d33c8a0dc3fd0dd03984220dc9709e8e0de43b"}, {"source": "cve@mitre.org", "url": "https://github.com/roundcube/roundcubemail/commit/a2334990c02f7cb77b1a8d6fa97fcd9e1b5cd1fb"}, {"source": "cve@mitre.org", "url": "https://github.com/roundcube/roundcubemail/releases/tag/1.6.18"}, {"source": "cve@mitre.org", "url": "https://github.com/roundcube/roundcubemail/releases/tag/1.7.3"}, {"source": "cve@mitre.org", "url": "https://roundcube.net/news/2026/08/09/security-updates-1.6.18-and-1.7.3"}], "sourceIdentifier": "cve@mitre.org", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-79"}], "source": "cve@mitre.org", "type": "Primary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[1.6.0,1.6.18)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[1.7.0,1.7.3)"}}], "enrichment": {"confidence": 95.0, "confidence_source": "inferred", "scores": [{"score": 95.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Webmail", "source": "cna", "vendor": "Roundcube"}, "product": "webmail", "vendor": "roundcube"}], "created": "2026-08-17T14:45:04.137721+00:00", "title": "Unvalidated CSS Proxy Response Causing XSS and Information Disclosure in Roundcube Webmail", "updated": "2026-08-17T15:00:08.167049+00:00", "vendors": ["roundcube", "roundcube$PRODUCT$webmail"]}