.0 before SP3 allows remote attackers to bypass firewall restrictions or cause a denial of service (crash) by sending improperly fragmented IP packets without the first fragment, which the TCP/IP stack incorrectly reassembles into a valid session. NIST National Vulnerability Database (NVD) -- services.nvd.nist.gov (CVE / CVSS / CPE). {"cve":{"id":"CVE-1999-1463","sourceIdentifier":"cve@mitre.org","published":"1997-07-10T04:00:00.000","lastModified":"2026-06-16T21:50:29.653","vulnStatus":"Modified","cveTags":[],"descriptions":[{"lang":"en","value":"Windows NT 4.0 before SP3 allows remote attackers to bypass firewall restrictions or cause a denial of service (crash) by sending improperly fragmented IP packets without the first fragment, which the TCP/IP stack incorrectly reassembles into a valid session."}],"affected":[{"source":"cve@mitre.org","affectedData":[{"vendor":"n/a","product":"n/a","versions":[{"version":"n/a","status":"affected"}]}]}],"metrics":{"cvssMetricV2":[{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"2.0","vectorString":"AV:N/AC:L/Au:N/C:N/I:N/A:P","baseScore":5.0,"accessVector":"NETWORK","accessComplexity":"LOW","authentication":"NONE","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"PARTIAL"},"baseSeverity":"MEDIUM","exploitabilityScore":10.0,"impactScore":2.9,"acInsufInfo":false,"obtainAllPrivilege":false,"obtainUserPrivilege":false,"obtainOtherPrivilege":false,"userInteractionRequired":false}]},"weaknesses":[{"source":"nvd@nist.gov","type":"Primary","description":[{"lang":"en","value":"NVD-CWE-Other"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:microsoft:windows_nt:*:sp3:*:*:*:*:*:*","versionEndIncluding":"4.0","matchCriteriaId":"E2D64573-E3F4-488D-B15E-2715AC2526AE"}]}]}],"references":[{"url":"http://www.securityfocus.com/archive/1/7219","source":"cve@mitre.org","tags":["Exploit","Patch","Vendor Advisory"]},{"url":"https://exchange.xforce.ibmcloud.com/vulnerabilities/528","source":"cve@mitre.org"},{"url":"http://www.securityfocus.com/archive/1/7219","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Exploit","Patch","Vendor Advisory"]},{"url":"https://exchange.xforce.ibmcloud.com/vulnerabilities/528","source":"af854a3a-2127-422b-91ae-364da2661108"}]}},