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Fencer Vulns
medium 5.9

CVE-2019-1040 json

Windows NTLM Tampering Vulnerability

published 2019-06-12 7 y ago modified 2026-06-17 4 mo ago also EUVD-2019-9625

cvss
5.9
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
48.0%
EPSS 48.0% chance of exploitation in 30 days, percentile 98%
public exploits
0
none known

Summary

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. To 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. The update addresses the vulnerability by hardening NTLM MIC protection on the server-side.

Patch / fix

Exploit prediction

48.04% chance of exploitation in the next 30 days, higher than 98% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N/E:P/RL:O/RC:C
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
CNA 3.0 5.9 CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N

Affected products

  • Microsoft Windows 10 Version 1703
  • Microsoft Windows 10 Version 1803
  • Microsoft Windows Server, version 1803 (Server Core Installation)
  • Microsoft Windows 10 Version 1809
  • Microsoft Windows Server 2019
  • Microsoft Windows Server 2019 (Server Core installation)
  • Microsoft Windows 10 Version 1709 for 32-bit Systems
  • Microsoft Windows 10 Version 1709
  • Microsoft Windows 10 Version 1903 for 32-bit Systems
  • Microsoft Windows 10 Version 1903 for x64-based Systems
  • Microsoft Windows 10 Version 1903 for ARM64-based Systems
  • Microsoft Windows Server, version 1903 (Server Core installation)
  • Microsoft Windows 10 Version 1507
  • Microsoft Windows 10 Version 1607
  • Microsoft Windows Server 2016
  • Microsoft Windows Server 2016 (Server Core installation)
  • Microsoft Windows 7
  • Microsoft Windows 7 Service Pack 1
  • Microsoft Windows 8.1
  • Microsoft Windows Server 2008 Service Pack 2
  • Microsoft Windows Server 2008 Service Pack 2 (Server Core installation)
  • Microsoft Windows Server 2008 Service Pack 2
  • Microsoft Windows Server 2008 R2 Systems Service Pack 1
  • Microsoft Windows Server 2008 R2 Service Pack 1
  • Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation)
  • Microsoft Windows Server 2012
  • Microsoft Windows Server 2012 (Server Core installation)
  • Microsoft Windows Server 2012 R2
  • Microsoft Windows Server 2012 R2 (Server Core installation)

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.