Microsoft Windows up to Server 2025 Container Isolation FS Filter Driver unionfs.sys privileges management

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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8.1$5k-$25k0.70

Summaryinfo

A vulnerability was found in Microsoft Windows up to Server 2025. It has been classified as very critical. This vulnerability affects unknown code of the file unionfs.sys of the component Container Isolation FS Filter Driver. Performing a manipulation results in privileges management. This vulnerability is reported as CVE-2026-97794. The attack requires a local approach. No exploit exists. It is suggested to install a patch to address this issue.

Detailsinfo

A vulnerability classified as very critical has been found in Microsoft Windows up to Server 2025. This affects an unknown code block of the file unionfs.sys of the component Container Isolation FS Filter Driver. The manipulation with an unknown input leads to a privileges management vulnerability. CWE is classifying the issue as CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Heap-based buffer overflow in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to elevate privileges locally.

The advisory is shared at msrc.microsoft.com. This vulnerability is uniquely identified as CVE-2026-97794 since 09/25/2026. The exploitability is told to be easy. An attack has to be approached locally. Technical details are known, but no exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 10/14/2026). MITRE ATT&CK project uses the attack technique T1068 for this issue.

Applying a patch is able to eliminate this problem.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

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Version

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Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.3
VulDB Meta Temp Score: 8.1

VulDB Base Score: 8.8
VulDB Temp Score: 8.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.8
CNA Vector (microsoft): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Privileges management
CWE: CWE-269 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔒

Timelineinfo

09/25/2026 CVE reserved
10/14/2026 +19 days Advisory disclosed
10/14/2026 +0 days VulDB entry created
10/14/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com
Product: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-97794 (🔒)
GCVE (CVE): GCVE-0-2026-97794
GCVE (VulDB): GCVE-100-419697

Entryinfo

Created: 10/14/2026 11:37
Changes: 10/14/2026 11:37 (64)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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