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High

Windows Telephony Service Heap-Based Buffer Overflow Privilege Escalation

IdentifiersCVE-2026-25188CWE-122· Heap-based Buffer Overflow

CVE-2026-25188 is a heap-based buffer overflow in the Windows Telephony Service. The provided content states that the flaw allows an unauthorized attacker to elevate privileges over an adjacent network by sending specially crafted traffic to a vulnerable server. Additional supporting context indicates successful exploitation could result in SYSTEM-level privileges. Based on the available information, the vulnerability is a memory corruption issue in the Telephony Service reachable via network traffic in an adjacent-network context; however, the specific vulnerable function or code path is not provided in the source material.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can allow an attacker to elevate privileges to SYSTEM on the target Windows server. This would give the attacker full control over the affected host, including the ability to execute code with the highest local privileges, install programs or services, modify system configuration, access sensitive data, and potentially use the compromised system for further lateral movement or persistence.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure by limiting network access to systems running the Windows Telephony Service, especially from adjacent or untrusted network segments. Restrict or disable the Telephony Service where it is not required, and use host-based and network-based filtering to block unsolicited traffic to the service. Network segmentation and minimizing service exposure can reduce the likelihood of exploitation until patches are deployed.

Remediation

Patch, then assume compromise.

Apply the Microsoft security update that addresses CVE-2026-25188 as part of the March 2026 Patch Tuesday release. Because the issue affects the Windows Telephony Service and can lead to SYSTEM-level privilege escalation from network-reachable attack traffic, affected systems should be prioritized for patching, especially servers or endpoints where the Telephony Service is enabled and reachable from adjacent-network segments.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
Microsoft CorporationWindowsoperating_system
Microsoft CorporationWindows 10 1607operating_system
Microsoft CorporationWindows 10 1809operating_system
Microsoft CorporationWindows 10 21h2operating_system
Microsoft CorporationWindows 10 22h2operating_system
Microsoft CorporationWindows 11 23h2operating_system
Microsoft CorporationWindows 11 24h2operating_system
Microsoft CorporationWindows 11 25h2operating_system
Microsoft CorporationWindows 11 26h1operating_system
Microsoft CorporationWindows Server 2012operating_system
Microsoft CorporationWindows Server 2012 R2operating_system
Microsoft CorporationWindows Server 2016operating_system
Microsoft CorporationWindows Server 2019operating_system
Microsoft CorporationWindows Server 2022operating_system
Microsoft CorporationWindows Server 2022 23h2operating_system
Microsoft CorporationWindows Server 2025operating_system
Microsoft CorporationWindows Server 23h2operating_system

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

3 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

3 SOURCESView more in app
What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity2

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES
MITRE CVE
cve.org · CVE-2026-25188
NVD
nvd.nist.gov/vuln/detail/CVE-2026-25188
MITRE CWE · CWE-122
Heap-based Buffer Overflow
Vendor Advisory
msrc.microsoft.com/update-guide/vulnerability/CVE-2026-25188