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major vulnerability· requires attention

Affects Windows core OS component with potential widespread privilege escalation across endpoints.

Systems

CVE-2026-25188

8.8
High
EPSS 0.55%Patch availableMar 11, 2026

Heap overflow in Windows Telephony Service enables network-based privilege escalation.

common questions

Is CVE-2026-25188 being exploited?

Not confirmed. CVE-2026-25188 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.55% probability of exploitation in the next 30 days.

How severe is CVE-2026-25188?

CVE-2026-25188 is rated High with a CVSS score of 8.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2026-25188?

Yes. A fix has been recorded for CVE-2026-25188. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2026-25188 affect?

CVE-2026-25188 affects Windows Telephony Service, Windows OS. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

What should I do about CVE-2026-25188?

Patch Windows via MS Update; restrict Telephony Service exposure.

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

executive summary
technical analysis
affected
Windows Telephony ServiceWindows OS
impact

Remote attacker on adjacent network can escalate privileges to SYSTEM on Windows hosts via Telephony Service.

action required

Patch when possible

affected versions
Microsoft Windows 10 Version 1607
  • affected>= 10.0.14393.0 and < 10.0.14393.8957
Microsoft Windows 10 Version 1809
  • affected>= 10.0.17763.0 and < 10.0.17763.8511
Microsoft Windows 10 Version 21H2
  • affected>= 10.0.19044.0 and < 10.0.19044.7058
Microsoft Windows 10 Version 22H2
  • affected>= 10.0.19045.0 and < 10.0.19045.7058
Microsoft Windows 11 version 22H3
  • affected>= 10.0.22631.0 and < 10.0.22631.6783
Microsoft Windows 11 Version 23H2
  • affected>= 10.0.22631.0 and < 10.0.22631.6783
Microsoft Windows 11 Version 24H2
  • affected>= 10.0.26100.0 and < 10.0.26100.8037
Microsoft Windows 11 Version 25H2
  • affected>= 10.0.26200.0 and < 10.0.26200.8037
Microsoft Windows 11 version 26H1
  • affected>= 10.0.28000.0 and < 10.0.28000.1719
Microsoft Windows Server 2012
  • affected>= 6.2.9200.0 and < 6.2.9200.25973
Microsoft Windows Server 2012 R2
  • affected>= 6.3.9600.0 and < 6.3.9600.23074
Microsoft Windows Server 2012 R2 (Server Core installation)
  • affected>= 6.3.9600.0 and < 6.3.9600.23074
Microsoft Windows Server 2012 (Server Core installation)
  • affected>= 6.2.9200.0 and < 6.2.9200.25973
Microsoft Windows Server 2016
  • affected>= 10.0.14393.0 and < 10.0.14393.8957
Microsoft Windows Server 2016 (Server Core installation)
  • affected>= 10.0.14393.0 and < 10.0.14393.8957
Microsoft Windows Server 2019
  • affected>= 10.0.17763.0 and < 10.0.17763.8511
Microsoft Windows Server 2019 (Server Core installation)
  • affected>= 10.0.17763.0 and < 10.0.17763.8511
Microsoft Windows Server 2022
  • affected>= 10.0.20348.0 and < 10.0.20348.4893
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation)
  • affected>= 10.0.25398.0 and < 10.0.25398.2207
Microsoft Windows Server 2025
  • affected>= 10.0.26100.0 and < 10.0.26100.32522
Microsoft Windows Server 2025 (Server Core installation)
  • affected>= 10.0.26100.0 and < 10.0.26100.32522

As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.

how to fix
Remediation steps are tailored for users whose stack is affected. Add this technology to your stack to see the fix checklist.
references
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