Windows 10 Version 1607: Memory Allocation with Excessive Size Value
CVE-2026-85324 is a high-severity memory allocation with excessive size value vulnerability in Windows 10 Version 1607 from Microsoft, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 10.0.14393.9612 as the first without the flaw, so updating Windows 10 Version 1607 to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.75% chance of exploitation within 30 days, higher than 56% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Windows 10 Version 1607 to 10.0.14393.9612 or a later version.
- Update Windows 10 Version 1809 to 10.0.17763.9376 or a later version.
- Update Windows Server 2012 to 6.2.9200.26434 or a later version.
- Read the advisory on msrc.microsoft.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Microsoft | Windows 10 Version 1607 | 10.0.14393.0 up to, but not including, 10.0.14393.9612 | 10.0.14393.9612 |
| Microsoft | Windows 10 Version 1809 | 10.0.17763.0 up to, but not including, 10.0.17763.9376 | 10.0.17763.9376 |
| Microsoft | Windows Server 2012 | 6.2.9200.0 up to, but not including, 6.2.9200.26434 | 6.2.9200.26434 |
| Microsoft | Windows Server 2012 (Server Core installation) | 6.2.9200.0 up to, but not including, 6.2.9200.26434 | 6.2.9200.26434 |
| Microsoft | Windows Server 2012 R2 | 6.3.9600.0 up to, but not including, 6.3.9600.23470 | 6.3.9600.23470 |
| Microsoft | Windows Server 2012 R2 (Server Core installation) | 6.3.9600.0 up to, but not including, 6.3.9600.23470 | 6.3.9600.23470 |
| Microsoft | Windows Server 2016 | 10.0.14393.0 up to, but not including, 10.0.14393.9612 | 10.0.14393.9612 |
| Microsoft | Windows Server 2016 (Server Core installation) | 10.0.14393.0 up to, but not including, 10.0.14393.9612 | 10.0.14393.9612 |
| Microsoft | Windows Server 2019 | 10.0.17763.0 up to, but not including, 10.0.17763.9376 | 10.0.17763.9376 |
| Microsoft | Windows Server 2019 (Server Core installation) | 10.0.17763.0 up to, but not including, 10.0.17763.9376 | 10.0.17763.9376 |
| Microsoft | Windows Server 2022 | 10.0.20348.0 up to, but not including, 10.0.20348.5761 | 10.0.20348.5761 |
| Microsoft | Windows Server 2025 | 10.0.26100.0 up to, but not including, 10.0.26100.33650 | 10.0.26100.33650 |
| Microsoft | Windows Server 2025 (Server Core installation) | 10.0.26100.0 up to, but not including, 10.0.26100.33650 | 10.0.26100.33650 |
| Microsoft | Windows 10 1607 | before 10.0.14393.9612 | 10.0.14393.9612 |
| Microsoft | Windows 10 1809 | before 10.0.17763.9376 | 10.0.17763.9376 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (microsoft.com).
Official description
Memory allocation with excessive size value in Active Directory Federation Services (AD FS) allows an unauthorized attacker to deny service over a network.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Memory Allocation with Excessive Size Value
The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.
How developers prevent this class of flaw
- Perform adequate input validation against any value that influences the amount of memory that is allocated. Define an appropriate strategy for handling requests that exceed the limit, and consider supporting a configuration option so that the administrator can extend the amount of memory to be used if necessary.
- Run your program using system-provided resource limits for memory. This might still cause the program to crash or exit, but the impact to the rest of the system will be minimized.
More Memory Allocation with Excessive Size Value vulnerabilities (CWE-789)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Recent Memory Allocation with Excessive Size Value vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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