dbcve.org
Windows 10 1507Operating system · Microsoft

CVE-2025-27481

HIGH · 8.8 CVSS v3.1 Published 2025-04-08
Fix available
A fix is available. Upgrade to 10.0.10240.20978 / 10.0.14393.7969 or later.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable No privileges

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
Stack-based buffer overflow in Windows Telephony Service allows an unauthorized attacker to execute code 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

Stack-based buffer overflow vulnerability in Windows Telephony Service allows remote code execution. The vulnerability stems from improper bounds checking when processing network input, enabling an attacker to overwrite stack memory and redirect execution flow.

MitigationApply Microsoft security updates for Windows Telephony Service immediately. Restrict network access to telephony services and disable unused telephony endpoints to reduce attack surface.

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:< 10.0.10240.20978
Windows 10 1607Operating system
Affected:< 10.0.14393.7969
Windows 10 1809Operating system
Affected:< 10.0.17763.7136
Windows 10 21h2Operating system
Affected:< 10.0.19044.5737
Windows 10 22h2Operating system
Affected:< 10.0.19045.5737
Windows 11 22h2Operating system
Affected:< 10.0.22621.5189
Windows 11 23h2Operating system
Affected:< 10.0.22631.5189
Windows 11 24h2Operating system
Affected:< 10.0.26100.3775

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

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

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 build version
    Run 'winver' or 'systeminfo' and note the OS Build number shown (e.g., 19045.5737 for Windows 10 22h2). Compare this to the fixed versions: 10.0.10240.20978 (1507), 10.0.14393.7969 (1607), 10.0.17763.7136 (1809), 10.0.19044.5737 (21h2), 10.0.19045.5737 (22h2), 10.0.22621.5189 (11 22h2), 10.0.22631.5189 (11 23h2), 10.0.26100.3775 (11 24h2).
    Affected if Your build number is lower than the fixed version for your Windows release.
  2. Identify Windows release version
    Run 'winver' or check 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to determine if you are on Windows 10 1507, 1607, 1809, 21h2, 22h2 or Windows 11 22h2, 23h2, 24h2.
    Affected if Your Windows release matches any of the affected versions listed in the CVE.
  3. Verify Telephony Service status
    Open Services (services.msc) and locate the 'Telephony' service, or run 'sc query TapiSrv' from an elevated command prompt to check if the service exists.
    Affected if The Telephony service is present on your system.
  4. Confirm service running state
    Check if the Telephony service is currently running. In Services console, look at the Status column, or run 'sc query TapiSrv' and check for STATE: RUNNING.
    Affected if The Telephony service is running. The vulnerability triggers when processing network input through this service.

You are affected if your Windows version/build falls within any of the affected ranges AND the Telephony service is present on your system.

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 10.0.10240.20978 / 10.0.14393.7969 / 10.0.17763.7136 or later
Fixed in 10.0.10240.2097810.0.14393.796910.0.17763.7136
Interim mitigation

Apply Microsoft security updates for Windows Telephony Service immediately. Restrict network access to telephony services and disable unused telephony endpoints to reduce attack surface.

Recommended fix High confidence

Apply the appropriate per-version cumulative security update to reach the fixed build (Windows 10 1507: 10.0.10240.20978 | 1607: 10.0.14393.7969 | 1809: 10.0.17763.7136 | 21h2: 10.0.19044.5737 | 22h2: 10.0.19045.5737 | Windows 11 22h2: 10.0.22621.5189 | 23h2: 10.0.22631.5189 | 24h2: 10.0.26100.3775)

  1. Open Settings > Update & Security > Windows Update and check for updates
  2. Install the cumulative security update for your Windows version (typically a monthly security update)
  3. Restart the system when prompted
  4. Verify the patch was applied by checking the installed updates for the relevant security bulletin (refer to MSRC for the specific KB number for this CVE)
Caveat Standard Windows security update risks apply; test in staging if possible

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

Fix this in Windows 10 1507 Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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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-2025-27481 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