CVE-2026-50508 is a network-exploitable NTLM spoofing vulnerability in Windows 10 1607, an operating system released in 2016. The CVSS 7.5 score reflects a genuine risk: an unauthenticated attacker on the network can spoof authentication sessions by manipulating NTLM challenge-response exchanges. The EPSS score of 0.08678 indicates this is not a speculative threat — the exploitability curve will climb as tooling matures and relay chains get weaponized. Here is what you should do: First, confirm whether NTLM is still enabled in your environment. Check the registry key HKLM\SYSTEM\CurrentControlSet\Control\Lsa\LMCompatibilityLevel — values below 5 mean NTLM v1 or LM hash is active. If you find it enabled, the immediate question is not whether to disable it but whether you can identify what breaks. Second, audit your authentication topology: enumerate systems publishing NTLM-authenticated services (print spoolers, file shares, legacy web apps) and map the trust relationships downstream from each relay point. The CVSS score measures one vulnerability; the blast radius extends through every system reachable via NTLM relay chains in your network segment. Third, treat this as a family event, not an isolated incident. NTLM spoofing vulnerabilities cluster around specific interaction points between legacy and modern authentication code paths — this is the fourth or fifth such CVE in the past three years. Your response should include a migration plan with a hard timeline, not a point-in-time patch. Finally, accept that patching Windows 10 1607 may not be the bottleneck — the bottleneck is the application dependency that requires NTLM. Your remediation timeline should be driven by application migration, not OS patching. If you are still running 1607 in production in 2026, you are operating on borrowed time regardless of this specific CVE.
CVE-2026-50508
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedExposure of sensitive information to an unauthorized actor in Windows NTLM allows an unauthorized attacker to perform spoofing over a network.
In the news
Third-party coverage- Microsoft June 2026 Patch Tuesday fixes 6 zero-days, 200 flaws
- Microsoft CVE Summary - Bleeping Computer
Surfaced from public web coverage — external links open in a new tab.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceThis Windows NTLM vulnerability allows unauthorized actors to expose sensitive authentication information, enabling attackers to perform network spoofing attacks. The flaw appears to involve how NTLM handles authentication exchanges, potentially allowing attackers to intercept or relay credentials to impersonate legitimate users or systems.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 10.0.14393.9234< 10.0.22631.7219< 10.0.19045.7417all versions= r2< 10.0.14393.9234< 10.0.20348.5256CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify Windows versionRun 'winver' or execute 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to obtain the installed Windows version and build numberAffected if The version falls within any of the affected ranges: Windows 10 1607 < 10.0.14393.9234, Windows 11 22h2 < 10.0.22631.7219, Windows Server 2004 < 10.0.19045.7417, Windows Server 2012 (any version including r2), Windows Server 2016 < 10.0.14393.9234, or Windows Server 2022 < 10.0.20348.5256
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Confirm NTLM authentication is enabledCheck the registry key 'HKLM\SYSTEM\CurrentControlSet\Control\Lsa\LMCompatibilityLevel' or run 'netlogon' query via 'nltest /domain_trusts /status' to determine if NTLM is permitted in the authentication flowAffected if NTLM authentication is allowed (value is 0-3) rather than restricted to NTLMv2 only or disabled entirely (values 4-5)
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Check NTLM network security settingsRun 'secpol.msc' and navigate to Local Policies > Security Options > 'Network security: LAN Manager authentication level', or query via 'reg query HKLM\SYSTEM\CurrentControlSet\Control\Lsa\MSV1_0'Affected if The setting allows LM or NTLM responses (Send LM & NTLM responses, Send LM & NTLM - use NTLMv2 session security if negotiated, or Send NTLM response only), exposing authentication artifacts
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Verify SMB signing is not enforcedRun 'Get-SmbServerConfiguration' in PowerShell or check 'reg query HKLM\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters\RequireSecuritySignature'Affected if SMB signing is disabled (value 0), allowing replay of captured authentication sessions over SMB
You are affected if your Windows version matches any of the listed affected versions AND NTLM authentication is enabled, as the vulnerability requires both the vulnerable version and active NTLM authentication to be exploitable.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped10.0.14393.923410.0.19045.741710.0.20348.5256
Apply Microsoft security updates for this NTLM vulnerability through Windows Update or manual patch deployment. Additionally, consider implementing NTLM blocking/signing policies and restricting NTLM usage where possible to reduce attack surface.
Upgrade to the specified build numbers: Windows 10 1607 to 10.0.14393.9234+, Windows 11 22h2 to 10.0.22631.7219+, Windows Server 2004 to 10.0.19045.7417+, Windows Server 2016 to 10.0.14393.9234+, Windows Server 2022 to 10.0.20348.5256+; Windows Server 2012/2012 R2 require migration to supported vers
- Identify the current Windows version by running 'winver' or 'systeminfo' in Command Prompt
- For Windows 10 1607: Upgrade to build 10.0.14393.9234 or later via Windows Update, or use Media Creation Tool to reinstall with latest updates
- For Windows 11 22h2: Upgrade to build 10.0.22631.7219 or later via Windows Update > Check for Updates
- For Windows Server 2004: Upgrade to build 10.0.19045.7417 or later via Windows Update or WSUS
- For Windows Server 2016: Upgrade to build 10.0.14393.9234 or later via Windows Update or WSUS
- For Windows Server 2022: Upgrade to build 10.0.20348.5256 or later via Windows Update or WSUS
- For Windows Server 2012/2012 R2: Microsoft lists 'all versions' as affected with no fixed version listed; these end-of-life products require migration to a supported Windows Server version (2016, 2019, or 2022)
- After upgrade, verify the fix by checking the installed KB patch number matches the security bulletin for this CVE
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-50508 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesCVE-2026-50508 is a network-exploitable NTLM spoofing vulnerability in Windows 10 1607, an operating system released in 2016. The CVSS 7.5 score reflects a genuine risk: an unauthenticated attacker on the network can spoof authentication sessions by manipulating NTLM challenge-response exchanges. The EPSS score of 0.08678 indicates this is not a speculative threat — the exploitability curve will climb as tooling matures and relay chains get weaponized. Here is what you should do: First, confirm whether NTLM is still enabled in your environment. Check the registry key HKLM\SYSTEM\CurrentControlSet\Control\Lsa\LMCompatibilityLevel — values below 5 mean NTLM v1 or LM hash is active. If you find it enabled, the immediate question is not whether to disable it but whether you can identify what breaks. Second, audit your authentication topology: enumerate systems publishing NTLM-authenticated services (print spoolers, file shares, legacy web apps) and map the trust relationships downstream from each relay point. The CVSS score measures one vulnerability; the blast radius extends through every system reachable via NTLM relay chains in your network segment. Third, treat this as a family event, not an isolated incident. NTLM spoofing vulnerabilities cluster around specific interaction points between legacy and modern authentication code paths — this is the fourth or fifth such CVE in the past three years. Your response should include a migration plan with a hard timeline, not a point-in-time patch. Finally, accept that patching Windows 10 1607 may not be the bottleneck — the bottleneck is the application dependency that requires NTLM. Your remediation timeline should be driven by application migration, not OS patching. If you are still running 1607 in production in 2026, you are operating on borrowed time regardless of this specific CVE.
Practitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-50508 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data