dbcve.org
Windows 10 1607Operating system · Microsoft

CVE-2026-49177

MEDIUM · 5.5 CVSS v3.1 Published 2026-07-14
Fix available
A fix is available. Upgrade to 10.0.14393.9339 / 10.0.17763.9020 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click 5 weeks old

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 · unedited
Out-of-bounds read in Windows TCP/IP allows an authorized attacker to disclose information locally.

In the news

Third-party coverage
Trending covered by 1 outlet this week · latest 1mo ago

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 confidence

An out-of-bounds read vulnerability exists in the Windows TCP/IP stack that allows a locally authenticated attacker to read sensitive memory contents beyond intended buffer boundaries, potentially exposing system information.

MitigationApply the relevant Windows security update(s) from Microsoft to patch the TCP/IP stack vulnerability.

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
Windows 10 1607Operating system
Affected:< 10.0.14393.9339
Windows 10 1809Operating system
Affected:< 10.0.17763.9020
Windows 10 21h2Operating system
Affected:< 10.0.19044.7548
Windows 10 22h2Operating system
Affected:< 10.0.19045.7548
Windows 11 24h2Operating system
Affected:< 10.0.26100.8875
Windows 11 25h2Operating system
Affected:< 10.0.26200.8875
Windows 11 26h1Operating system
Affected:< 10.0.28000.2269< 10.0.28000.2525
Windows Server 2012Operating system
Affected:all versions= r2

CVSS 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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:L/AC:L/PR:L/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 checks

Work through these to decide whether this CVE applies to you.

  1. Check Windows version and build number
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to get the exact Windows version and build number
    Affected if The build number is lower than the thresholds in the affected versions list (e.g., below 14393.9339 for Windows 10 1607, below 17763.9020 for Windows 10 1809, etc.)
  2. Verify TCP/IP stack is in use
    Confirm the system has networking enabled. Run 'netsh interface ipv4 show config' or check that network adapters are present and active
    Affected if The system has any active network adapters with TCP/IP enabled (which is the default Windows configuration)
  3. Confirm local access authentication capability
    Verify that local user accounts exist on the system by running 'net user' or checking Local Users and Groups (lusrmgr.msc)
    Affected if Local authentication is possible (standard on all Windows workstations and servers)

The system is likely affected if it runs a Windows version within the affected ranges AND has TCP/IP networking enabled, which is the default state.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 10.0.14393.9339 / 10.0.17763.9020 / 10.0.19044.7548 or later
Fixed in 10.0.14393.933910.0.17763.902010.0.19044.7548
Interim mitigation

Apply the relevant Windows security update(s) from Microsoft to patch the TCP/IP stack vulnerability.

Recommended fix High confidence

Windows 10 1607: 10.0.14393.9339 | Windows 10 1809: 10.0.17763.9020 | Windows 10 21h2: 10.0.19044.7548 | Windows 10 22h2: 10.0.19045.7548 | Windows 11 24h2: 10.0.26100.8875 | Windows 11 25h2: 10.0.26200.8875 | Windows 11 26h1: 10.0.28000.2525 | Windows Server 2012/R2: migrate to supported version

  1. Identify the current Windows version by running 'winver' or 'systeminfo' from command prompt
  2. Determine if the installed version is below the fixed threshold for your Windows release
  3. For Windows 10 1607: Upgrade to version 10.0.14393.9339 or later via Windows Update or Microsoft Update Catalog
  4. For Windows 10 1809: Upgrade to version 10.0.17763.9020 or later via Windows Update
  5. For Windows 10 21h2: Upgrade to version 10.0.19044.7548 or later
  6. For Windows 10 22h2: Upgrade to version 10.0.19045.7548 or later
  7. For Windows 11 24h2: Upgrade to version 10.0.26100.8875 or later
  8. For Windows 11 25h2: Upgrade to version 10.0.26200.8875 or later
Caveat Windows Server 2012/R2 is end-of-life with no security updates; migration to newer Windows Server required; Windows 10 1607/1809 may require ESU (Extended Security Updates) for continued support

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Windows 10 1607 Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-49177 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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