CVE-2026-41096Public exploitNetwork attack vector

Unauthenticated code execution via DNS truncation miscalculation

Published May 12, 2026 · Updated May 12, 2026

Heap-based buffer overflow in Microsoft Windows DNS Client allows remote attackers to execute code through a crafted DNS response. DnsRawTruncateMessageForUdp in dnsapi.dll miscalculates the destination pointer while truncating a response with QDCOUNT zero and a large OPT record, causing a 604-byte heap overwrite. No authentication or user interaction is required, but the vulnerable client must process a response supplied by an attacker-controlled DNS server.

CVSS severity9.8
Critical
EPSS probability1.93%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in Microsoft Windows DNS Client allows remote attackers to execute code through a crafted DNS response. DnsRawTruncateMessageForUdp in dnsapi.dll miscalculates the destination pointer while truncating a response with QDCOUNT zero and a large OPT record, causing a 604-byte heap overwrite. No authentication or user interaction is required, but the vulnerable client must process a response supplied by an attacker-controlled DNS server.

The record

CVE
CVE-2026-41096
Published
May 12, 2026
Updated
May 12, 2026
Vendor
Microsoft
Product
Windows Server 2025 (Server Core installation)
Classifications
CWE-122, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 12, 2026CVE publishedPublication date reported by the CVE source.
  2. May 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.0.26100.0 <10.0.26100.32860

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Windows Server 2025 (Server Core installation)version=10.0.26100.0 <10.0.26100.32860
Microsoft · Windows 11, version 25H2version=10.0.26200.0 <10.0.26200.8457
Microsoft · Windows 11, version 24H2version=10.0.26100.0 <10.0.26100.8457
Microsoft · Windows Server 2022, 23H2 Edition (Server Core installation)version=10.0.25398.0 <10.0.25398.2330
Microsoft · Windows 11 Version 22H3version=10.0.22631.0 <10.0.22631.7079
Microsoft · Windows 11, version 26H1version=10.0.28000.0 <10.0.28000.2113
Microsoft · Windows 11 Version 23H2version=10.0.22631.0 <10.0.22631.7079
Microsoft · Windows Server 2025version=10.0.26100.0 <10.0.26100.32860

Published CVSS scores

9.8Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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