Unauthenticated service interruption via type confusion
Published Sep 8, 2026 · Updated Sep 9, 2026
Type confusion in Microsoft Windows DHCP Server allows remote attackers to interrupt the DHCP service through network traffic. The server accesses a resource using an incompatible type while processing attacker-controlled network input; Microsoft has not disclosed a narrower code locus or packet field. No authentication or user interaction is required, and the documented consequence is service interruption rather than data disclosure or modification.
Summary
What happened
Type confusion in Microsoft Windows DHCP Server allows remote attackers to interrupt the DHCP service through network traffic. The server accesses a resource using an incompatible type while processing attacker-controlled network input; Microsoft has not disclosed a narrower code locus or packet field. No authentication or user interaction is required, and the documented consequence is service interruption rather than data disclosure or modification.
The record
- CVE
- CVE-2026-77890
- 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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