CVE-2026-72971
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.
CSIRTS triage
- What
- Link following vulnerability in unionfs.sys allows an authorized attacker to perform tampering locally.
- Who is affected
- Windows Container environments with unpatched unionfs.sys are affected.
- Urgency
- Medium priority; local tampering vulnerability not currently exploited but affects authenticated users.
- Action
- Apply the latest Windows Container security update.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Low exploitation risk0.36% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 29% of all EPSS-scored CVEs.
Advisory coverage (3)
- unknownexploitedMicrosoft Monthly Security Update (August 2026)hkcert · 2026-08-12
- mediumCVE-2026-72971: Improper link resolution before file access ('link following') in Windows Container Isolation …nvd · 2026-08-11
- mediumCVE-2026-72971: Windows Container Isolation FS Filter Driver (unionfs.sys) Tampering Vulnerabilitymsrc · 2026-08-11
External references
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