Microsoft Windows up to Server 2025 Windows Container Isolation FS Filter Driver unionfs.sys link following

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
4.3$5k-$25k1.75

Summaryinfo

A vulnerability was found in Microsoft Windows up to Server 2025. It has been classified as problematic. The impacted element is an unknown function of the file unionfs.sys of the component Windows Container Isolation FS Filter Driver. This manipulation causes link following. This vulnerability is tracked as CVE-2026-97790. The attack is restricted to local execution. No exploit exists. It is recommended to apply a patch to fix this issue.

Detailsinfo

A vulnerability was found in Microsoft Windows up to Server 2025. It has been declared as problematic. Affected by this vulnerability is an unknown code block of the file unionfs.sys of the component Windows Container Isolation FS Filter Driver. The manipulation with an unknown input leads to a link following vulnerability. The CWE definition for the vulnerability is CWE-59. The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource. As an impact it is known to affect integrity. The summary by CVE is:

Improper link resolution before file access ('link following') in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to perform tampering locally.

It is possible to read the advisory at msrc.microsoft.com. This vulnerability is known as CVE-2026-97790 since 09/25/2026. The exploitation appears to be easy. Attacking locally is a requirement. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 10/14/2026).

Applying a patch is able to eliminate this problem.

Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.4
VulDB Meta Temp Score: 4.3

VulDB Base Score: 3.3
VulDB Temp Score: 3.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 5.5
CNA Vector (microsoft): 🔒

CVSSv2info

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

Exploitinginfo

Class: Link following
CWE: CWE-59
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-2026-97790 (🔒)
GCVE (CVE): GCVE-0-2026-97790
GCVE (VulDB): GCVE-100-419767

Entryinfo

Created: 10/14/2026 12:00
Changes: 10/14/2026 12:00 (64)
Complete: 🔍
Cache ID: 216::103

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