{"id":"CVE-2023-35311","kind":"vulnerability","aliases":["CVE-2023-35311"],"related":[],"title":"Microsoft Outlook Security Feature Bypass Vulnerability","description":"Microsoft Outlook contains a security feature bypass vulnerability that allows an attacker to bypass the Microsoft Outlook Security Notice prompt.\n\nCISA required action: Apply updates per vendor instructions or discontinue use of the product if updates are unavailable.","summary":"Microsoft Outlook has a security feature bypass that lets an attacker skip the Outlook Security Notice prompt. CISA lists it as actively exploited, and the sources give no further detail on what the attacker gets after the bypass.","severity":"high","cvss":8.8,"epss":null,"exploited":true,"exploited_at":"2023-07-11T00:00:00+00:00","products":[{"name":"Microsoft Outlook","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft 365 apps","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft office 2019","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft office 2021","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft outlook","fixed":[],"affected":"= 2013","ecosystem":"vendor"},{"name":"microsoft outlook","fixed":[],"affected":"= 2016","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["exploited","microsoft-outlook","vendor","windows"],"not_affected_if":["unknown"],"how_to_check":null,"fix":"Apply Microsoft's updates for Outlook per the vendor instructions, or stop using the product if no update is available (CISA required action).","status":"open","published_at":"2023-07-11T00:00:00+00:00","first_seen_at":"2026-10-23T19:11:51+00:00","triaged_at":"2026-10-23T21:04:58+00:00","updated_at":"2026-10-23T22:29:04+00:00","category":"vendor","confidence":0.5,"triage":{"at":"2026-10-23T21:04:58Z","model":"claude-haiku-5-5","output":{"fix":"Apply Microsoft's updates for Outlook per the vendor instructions, or stop using the product if no update is available (CISA required action).","reach":"unknown","impact":"medium","summary":"Microsoft Outlook has a security feature bypass that lets an attacker skip the Outlook Security Notice prompt. CISA lists it as actively exploited, and the sources give no further detail on what the attacker gets after the bypass.","category":"vendor","who_cares":["microsoft-outlook","windows"],"confidence":0.5,"needs_auth":"unknown","worst_case":"Attacker bypasses the Outlook Security Notice prompt, exact follow-on impact unknown","analyst_note":"Check Microsoft's advisory for CVE-2023-35311 for affected versions, fixed builds, and how the bypass is triggered and what it grants.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["unknown"],"user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000464,"input_tokens":2812,"output_tokens":366,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2023':8A,11A '-35311':9A,12A '2019':20A '2021':23A '365':16A 'action':94C 'activ':55B 'allow':81C 'appli':95C 'apps':17A 'attack':44B,67B,83C 'bypass':5A,40B,71B,78C,85C 'cisa':51B,92C 'contain':74C 'cve':7A,10A 'detail':63B 'discontinu':101C 'exploit':28B,56B 'featur':4A,39B,77C 'get':68B 'give':60B 'instruct':99C 'let':42B 'list':52B 'microsoft':1A,13A,15A,18A,21A,24A,26A,30B,34B,72C,87C 'microsoft-outlook':29B 'notic':49B,90C 'office':19A,22A 'outlook':2A,14A,25A,27A,31B,35B,47B,73C,88C 'per':97C 'product':105C 'prompt':50B,91C 'requir':93C 'secur':3A,38B,48B,76C,89C 'skip':45B 'sourc':59B 'unavail':109C 'updat':96C,107C 'use':102C 'vendor':32B,98C 'vulner':6A,79C 'window':33B","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2023-07-11T00:00:00+00:00","kev":{"dateAdded":"2023-07-11","dueDate":"2023-08-01","requiredAction":"Apply updates per vendor instructions or discontinue use of the product if updates are unavailable.","knownRansomwareCampaignUse":"Unknown"},"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","cvss_by":"secure@microsoft.com","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2023-35311","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2023-35311","severity":null,"published_at":"2023-07-11T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:51+00:00","fetched_at":"2026-10-25T11:39:15+00:00","note":null},{"source":"nvd","external_id":"CVE-2023-35311","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-35311","severity":null,"published_at":"2023-07-11T18:15:17+00:00","modified_at":"2026-10-08T10:35:03+00:00","first_seen_at":"2026-10-23T22:29:04+00:00","fetched_at":"2026-10-23T22:29:04+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}