{"cve":"CVE-2019-1040","nvd":{"published":"2019-06-12T14:29:03.713","modified":"2026-06-17T02:27:40.310","status":"Modified","description":"A tampering vulnerability exists in Microsoft Windows when a man-in-the-middle attacker is able to successfully bypass the NTLM MIC (Message Integrity Check) protection. An attacker who successfully exploited this vulnerability could gain the ability to downgrade NTLM security features.\nTo exploit this vulnerability, the attacker would need to tamper with the NTLM exchange. The attacker could then modify flags of the NTLM packet without invalidating the signature.\nThe update addresses the vulnerability by hardening NTLM MIC protection on the server-side.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N","score":5.3},"cwes":[],"references":["https://msrc.microsoft.com/update-guide/vulnerability/CVE-2019-1040","https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1040"],"products":["microsoft:windows_10","microsoft:windows_7","microsoft:windows_8.1","microsoft:windows_rt_8.1","microsoft:windows_server_2008","microsoft:windows_server_2012","microsoft:windows_server_2016","microsoft:windows_server_2019"],"source":"nvd","synced_at":"2026-10-19T20:57:00.690689396+00:00"},"epss":{"cve":"CVE-2019-1040","score":0.48043,"percentile":0.98856,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}