Unauthenticated service denial via unbounded resource allocation
Published Oct 13, 2026 · Updated Oct 13, 2026
Resource exhaustion in Microsoft Windows Server AD FS allows remote attackers to interrupt federation service over a network. The supplied source identifies unbounded resource allocation, but the affected request handler, resource type, and trigger are not publicly verified. Exposure requires a reachable AD FS deployment; the available evidence does not distinguish a hang from a crash or establish broader host impact.
Summary
What happened
Resource exhaustion in Microsoft Windows Server AD FS allows remote attackers to interrupt federation service over a network. The supplied source identifies unbounded resource allocation, but the affected request handler, resource type, and trigger are not publicly verified. Exposure requires a reachable AD FS deployment; the available evidence does not distinguish a hang from a crash or establish broader host impact.
The record
- CVE
- CVE-2026-85321
- Published
- Oct 13, 2026
- Updated
- Oct 13, 2026
- Vendor
- Microsoft Corporation
- Product
- Windows Server 2019
- Classifications
- T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 13, 2026CVE publishedPublication date reported by the CVE source.
- Oct 13, 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 <10.0.17763.9376
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
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.
Activity data is delayed. The latest report is Sep 28, 2026.
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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