CVE-2026-85321ImportantDoSNetwork
Active Directory Federation Services (AD FS) Denial of Service Vulnerability
Assessment
Allocation of resources without limits or throttling in Active Directory Federation Services (AD FS) allows an unauthorized attacker to deny service over a network.
- Severity
- Important
- CVSS base score
- 7.5CVSS:3.1/
AV:N/ AC:L/ PR:N/ UI:N/ S:U/ C:N/ I:N/ A:H/ E:U/ RL:O/ RC:C - Impact
- Denial of Service
- EPSS, next 30 days
- Not scored yet
- Public exploit code
- No Nuclei template lists it
- Exploitability
- Exploitation Unlikely
- Publicly disclosed
- No
- Customer action
- Required: apply the update
- Component
- Active Directory Federation Services (AD FS)
- Weakness
- CWE-770: Allocation of Resources Without Limits or Throttling
- Issued by
- Microsoft
- Published
- 13 Oct 2026 · October 2026
- Last revised
- 13 Oct 2026
CVSS 3.1 base metricsRed raises the risk · green lowers it
- Attack vector
- NetworkAV:N
- Attack complexity
- LowAC:L
- Privileges required
- NonePR:N
- User interaction
- NoneUI:N
- Scope
- UnchangedS:U
- Confidentiality
- NoneC:N
- Integrity
- NoneI:N
- Availability
- HighA:H
Updates that fix it
5 KBs| KB | Type | Restart | Applies to | Other CVEs |
|---|---|---|---|---|
| KB5126646 | Security Update | Required | Windows Server 2025, Windows Server 2025 (Server Core installation) | All CVEs in KB5126646 |
| KB5126651 | Security Update | Required | Windows Server 2019, Windows Server 2019 (Server Core installation) | All CVEs in KB5126651 |
| KB5126655 | Security Update | Required | Windows Server 2022, Windows Server 2022 (Server Core installation) | All CVEs in KB5126655 |
| KB5126836 | Security Update | Required | Windows Server 2012 R2, Windows Server 2012 R2 (Server Core installation) | All CVEs in KB5126836 |
| KB5126868 | Security Update | Required | Windows Server 2016, Windows Server 2016 (Server Core installation) | All CVEs in KB5126868 |
What changed
First observed 14 Oct 2026No field changes in the recorded history.
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