CVE-2019-1040
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.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 48.0%, higher than 99% of all known CVEs. Patch or mitigate before the next change window.
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. 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.
- CVSS 3.1
- 5.3 MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
- EPSS
- 48.04% probability · 99th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Affected
- 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
- secure@microsoft.com
EPSS moved from 33.3% on 21 September 2026 to 48.0% on 27 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.