{"id":"CVE-2026-72971","title":"Windows Container Isolation FS Filter Driver (unionfs.sys) Tampering Vulnerability","summary":"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.","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C","cvssSource":"cna","cwe":["CWE-59"],"vendor":"Microsoft","product":"Windows 11 version 26H1","affected":["windows_11_version_26h1 >= 10.0.28000.0 < 10.0.28000.2704"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-08-11T19:20:18.522655Z"},"published":"2026-08-11","updated":"2026-09-16","sourceUpdated":"2026-09-16T16:25:07.839Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72971","references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-72971","label":"Windows Container Isolation FS Filter Driver (unionfs.sys) Tampering Vulnerability"}],"tags":["cve.org"],"epss":0.00473,"epssPercentile":0.40062,"ingestedAt":"2026-09-08T19:08:49.657Z","slug":"CVE-2026-72971","body":"## Overview\n\nImproper link resolution before file access ('link following') in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to perform tampering locally.\n\n## Affected\n\n- `windows_11_version_26h1 >= 10.0.28000.0 < 10.0.28000.2704`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}