Unauthenticated service interruption via DHCP type confusion
Published Sep 8, 2026 · Updated Sep 9, 2026
Type confusion in Microsoft Windows DHCP Server allows remote attackers to interrupt DHCP service through crafted network requests. Microsoft identifies incompatible-type resource access in DHCP Server but has not disclosed the specific code locus or malformed field that triggers it. Exploitation requires network reachability to an affected host and no authentication; the reported consequence is loss of availability, not data access or code execution.
Summary
What happened
Type confusion in Microsoft Windows DHCP Server allows remote attackers to interrupt DHCP service through crafted network requests. Microsoft identifies incompatible-type resource access in DHCP Server but has not disclosed the specific code locus or malformed field that triggers it. Exploitation requires network reachability to an affected host and no authentication; the reported consequence is loss of availability, not data access or code execution.
The record
- CVE
- CVE-2026-77889
- Published
- Sep 8, 2026
- Updated
- Sep 9, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-843, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 8, 2026CVE publishedPublication date reported by the CVE source.
- Sep 9, 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.
- Affected versionversion=10.0.17763.0 <10.0.17763.9245
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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