{"id":"CVE-2026-95989","kind":"vulnerability","aliases":["CVE-2026-95989"],"related":[],"title":"Windows vhdmp.sys: use-after-free lets a local user gain higher privileges","description":"Use after free in vhdmp.sys allows an authorized attacker to elevate privileges locally.","summary":"A use-after-free bug in the Windows virtual hard disk driver (vhdmp.sys) lets an authorized local user elevate privileges. An attacker who already has a local account can gain higher system rights.","severity":"high","cvss":7.0,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["infrastructure","local-users","windows"],"not_affected_if":["no-local-untrusted-users"],"how_to_check":"Unknown until the MSRC entry for CVE-2026-95989 lists affected builds and KBs. Meanwhile: check the installed Windows build (winver) against the November 2026 cumulative update for your Windows version in the Microsoft Security Update Guide, and see whether untrusted local users or Hyper-V/VHD mounting are in play.","fix":null,"status":"open","published_at":"2026-11-10T19:21:55+00:00","first_seen_at":"2026-11-10T19:25:26+00:00","triaged_at":"2026-11-10T19:49:38+00:00","updated_at":"2026-11-10T20:14:32+00:00","category":"infrastructure","confidence":0.3,"triage":{"at":"2026-11-10T19:49:38Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"Windows vhdmp.sys: use-after-free lets a local user gain higher privileges","impact":"high","summary":"A use-after-free bug in the Windows virtual hard disk driver (vhdmp.sys) lets an authorized local user elevate privileges. An attacker who already has a local account can gain higher system rights.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["windows","local-users"],"confidence":0.5,"fix_status":"unknown","needs_auth":"yes","worst_case":"local user gains SYSTEM-level privileges on the machine","analyst_note":"Find the Microsoft advisory for CVE-2026-95989 to confirm affected Windows builds and the patch.","how_to_check":"- unknown","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["no-local-untrusted-users"],"who_is_affected":"Affects Windows systems with the vhdmp.sys driver, which handles virtual hard disks. Exposure requires an attacker who already has a local, authorized account on the machine. unknown whether the sources list specific Windows builds.","user_interaction":"no","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000666,"input_tokens":4478,"output_tokens":436,"severity_before":"high"},"analyst_status":"done","analyst_note":"Find the Microsoft advisory for CVE-2026-95989 to confirm affected Windows builds and the patch.","search":"'-2026':15A,18A '-95989':16A,19A 'account':53B 'allow':64C 'alreadi':49B 'attack':47B,67C 'author':41B,66C 'bug':30B 'cve':14A,17A 'disk':36B 'driver':37B 'elev':44B,69C 'free':6A,29B,61C 'gain':11A,55B 'hard':35B 'higher':12A,56B 'infrastructur':20B 'let':7A,39B 'local':9A,22B,42B,52B,71C 'local-us':21B 'privileg':13A,45B,70C 'right':58B 'system':57B 'use':4A,27B,59C 'use-after-fre':3A,26B 'user':10A,23B,43B 'vhdmp.sys':2A,38B,63C 'virtual':34B 'window':1A,24B,33B","nicknames":[],"mitigations":[],"who_affected":"Windows systems with the vhdmp.sys virtual hard disk driver, exploitable only by someone who already has a local account (CVSS 7.0, AV:L/AC:H/PR:L). Specific Windows builds are not confirmed yet. Single-user machines with no untrusted local users are lower risk.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"unknown","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["high","infrastructure","localusers","windows"],"campaign_type":null,"search_a":"'-2026':15A,18A '-95989':16A,19A 'cve':14A,17A 'free':6A 'gain':11A 'higher':12A 'let':7A 'local':9A 'privileg':13A 'use':4A 'use-after-fre':3A 'user':10A 'vhdmp.sys':2A 'window':1A","search_b":"'account':53B 'alreadi':49B 'attack':47B 'author':41B 'bug':30B 'disk':36B 'driver':37B 'elev':44B 'free':29B 'gain':55B 'hard':35B 'higher':56B 'infrastructur':20B 'let':39B 'local':22B,42B,52B 'local-us':21B 'privileg':45B 'right':58B 'system':57B 'use':27B 'use-after-fre':26B 'user':23B,43B 'vhdmp.sys':38B 'virtual':34B 'window':24B,33B","search_c":"'allow':64C 'attack':67C 'author':66C 'elev':69C 'free':61C 'local':71C 'privileg':70C 'use':59C 'vhdmp.sys':63C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T19:21:55+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","cvss_by":"secure@microsoft.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-95989","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-95989","severity":null,"published_at":"2026-11-10T19:21:55+00:00","modified_at":"2026-11-10T19:21:55+00:00","first_seen_at":"2026-11-10T19:25:26+00:00","fetched_at":"2026-11-10T19:25:26+00:00","note":null},{"source":"analyst","external_id":"CVE-2026-95989:2625","url":null,"severity":null,"published_at":"2026-11-10T20:14:32+00:00","modified_at":"2026-11-10T20:14:32+00:00","first_seen_at":"2026-11-10T20:14:32+00:00","fetched_at":"2026-11-10T20:14:32+00:00","note":"Could not read the MSRC advisory (JS-only page, web-cli/WebFetch returned nothing; NVD page empty too). No builds, KB or fix confirmed; nothing verified. Search/X not tried beyond this. Revisit when MSRC text is available."}],"documents":[],"disclosures":[],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}