CVE-2026-21253
Analyzed
Analyzed - Analysis Complete
Use-After-Free in Mailslot File System Enables Local Privilege Escalation
Publication date: 2026-02-10
Last updated on: 2026-03-27
Assigner: Microsoft Corporation
Description
Description
Use after free in Mailslot File System allows an authorized attacker to elevate privileges locally.
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| microsoft | windows_server_2012 | r2 |
| microsoft | windows_server_2012 | * |
| microsoft | windows_10_1607 | to 10.0.14393.8868 (exc) |
| microsoft | windows_10_1607 | to 10.0.14393.8868 (exc) |
| microsoft | windows_10_1809 | to 10.0.17763.8389 (exc) |
| microsoft | windows_11_24h2 | to 10.0.26100.7781 (exc) |
| microsoft | windows_11_24h2 | to 10.0.26100.7781 (exc) |
| microsoft | windows_11_23h2 | to 10.0.22631.6649 (exc) |
| microsoft | windows_11_23h2 | to 10.0.22631.6649 (exc) |
| microsoft | windows_11_25h2 | to 10.0.26200.7781 (exc) |
| microsoft | windows_11_25h2 | to 10.0.26200.7781 (exc) |
| microsoft | windows_10_22h2 | to 10.0.19045.6937 (exc) |
| microsoft | windows_10_22h2 | to 10.0.19045.6937 (exc) |
| microsoft | windows_10_22h2 | to 10.0.19045.6937 (exc) |
| microsoft | windows_10_21h2 | to 10.0.19044.6937 (exc) |
| microsoft | windows_10_21h2 | to 10.0.19044.6937 (exc) |
| microsoft | windows_10_21h2 | to 10.0.19044.6937 (exc) |
| microsoft | windows_10_1809 | to 10.0.17763.8389 (exc) |
| microsoft | windows_server_2016 | to 10.0.14393.8868 (exc) |
| microsoft | windows_server_2019 | to 10.0.17763.8389 (exc) |
| microsoft | windows_server_2022 | to 10.0.20348.4711 (exc) |
| microsoft | windows_server_2022_23h2 | to 10.0.25398.2149 (exc) |
| microsoft | windows_server_2025 | to 10.0.26100.32313 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-416 | The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is a use after free issue in the Mailslot File System. It allows an authorized attacker to elevate their privileges locally on the affected system.
How can this vulnerability impact me? :
The impact of this vulnerability is an elevation of privilege, meaning an attacker who already has some level of access can gain higher privileges on the system. This can lead to full control over the affected system.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
I don't know
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