CVE-2019-1040
Status: ModifiedMedium (5.3)—💥 PoC
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
- Version: 3.1
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
- Base score: 5.3
Exploitation probability (EPSS)
- Probability of exploitation in the next 30 days: 48%
- Percentile among all scored CVEs: 99
- Score date: 10/9/2026
EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).
💥 Public exploits
Exploit code or detection templates are publicly available. This is not the same as confirmed active exploitation (KEV), but it raises the risk: patch with priority.
- Proof of concept on GitHub (unverified) · List of proofs of concept on GitHub
⚠️ GitHub proofs of concept are not verified: some are fake or contain malware. Never run them outside an isolated lab.
Affected technologies (8)
CWEs
- NVD-CWE-noinfo
References
Raw JSON (NVD)
Show
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"value": "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."
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