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Windows 10 1507Operating system · Microsoft

CVE-2025-29956

MEDIUM · 5.4 CVSS v3.1 Published 2025-05-13
Fix available
A fix is available. Upgrade to 10.0.10240.21014 / 10.0.14393.8066 or later.
See remediation →
58/100
Remediation priority · Elevated
Remotely reachable

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
Buffer over-read in Windows SMB allows an authorized attacker to disclose information over a network.

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

A buffer over-read vulnerability exists in Windows SMB (Server Message Block) that allows an authenticated attacker to read beyond the boundaries of allocated memory buffers, potentially exposing sensitive information in memory. The vulnerability is exploitable over the network and requires the attacker to have valid credentials for SMB access.

MitigationApply Microsoft security updates for Windows SMB when available, or implement network-level access controls to limit SMB access to authorized users and systems only.

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 1507Operating system
Affected:< 10.0.10240.21014
Windows 10 1607Operating system
Affected:< 10.0.14393.8066
Windows 10 1809Operating system
Affected:< 10.0.17763.7314
Windows 10 21h2Operating system
Affected:< 10.0.19044.5854
Windows 10 22h2Operating system
Affected:< 10.0.19045.5854
Windows 11 22h2Operating system
Affected:< 10.0.22621.5335
Windows 11 23h2Operating system
Affected:< 10.0.22631.5335
Windows 11 24h2Operating system
Affected:< 10.0.26100.4061

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
Network
Complexity
High
Privileges
Low
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
Low

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:N/A:L

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. Verify SMB server is enabled
    Run 'Get-Service -Name Server' in PowerShell. The Server service (LanmanServer) must be running for SMB to be exposed.
    Affected if SMB server service is not running (the vulnerability cannot be exploited if SMB is disabled)
  2. Confirm Windows version
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Version"' and compare the build number to the affected ranges: Windows 10 1507 < 10240.21014, 1607 < 14393.8066, 1809 < 17763.7314, 21h2 < 19044.5854, 22h2 < 19045.5854; Windows 11 22h2 < 22621.5335, 23h2 < 22631.5335, 24h2 < 26100.4061.
    Affected if The installed Windows build number falls below the fixed version for your release branch
  3. Check SMB protocol versions enabled
    Run 'Get-SmbServerConfiguration | Select-Object SMB1Enabled, SMB2Enabled' in PowerShell. The vulnerability exists in SMB 2.x/3.x implementations.
    Affected if SMB2Enabled or SMB3Enabled is True (SMB1 alone does not contain this specific flaw)
  4. Verify SMB ports are listening
    Run 'Test-NetConnection -ComputerName localhost -Port 445' or 'netstat -an | findstr "445"' to confirm the SMB TCP port is open and listening.
    Affected if Port 445 is open and listening (network exploitation requires this)

Your system is affected if SMB server is enabled, the Windows version is below the fixed build number for your release, and SMB2/SMB3 is active on a listening port.

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 10.0.10240.21014 / 10.0.14393.8066 / 10.0.17763.7314 or later
Fixed in 10.0.10240.2101410.0.14393.806610.0.17763.7314
Interim mitigation

Apply Microsoft security updates for Windows SMB when available, or implement network-level access controls to limit SMB access to authorized users and systems only.

Recommended fix High confidence

Install the latest Windows security updates (monthly patch Tuesday or later) matching your Windows version to reach the minimum fixed build numbers listed above

  1. Open Windows Settings and navigate to Update & Security > Windows Update
  2. Click 'Check for updates' to download and install the latest security updates
  3. Alternatively, manually update by downloading the specific security update from the Microsoft Update Catalog for your Windows version
  4. Ensure the installed build number meets or exceeds the minimum fixed version for your Windows release: Windows 10 1507: 10.0.10240.21014, Windows 10 1607: 10.0.14393.8066, Windows 10 1809: 10.0.17763.7314, Windows 10 21h2: 10.0.19044.5854, Windows 10 22h2: 10.0.19045.5854, Windows 11 22h2: 10.0.22621.5335, Windows 11 23h2: 10.0.22631.5335, Windows 11 24h2: 10.0.26100.4061
  5. Verify the update by checking the Windows version (winver command)
Caveat Standard Windows update process; minimal risk of breaking changes in monthly security updates

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

Fix this in Windows 10 1507 Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.

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-2025-29956 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