{"id":"CVE-2024-21413","kind":"vulnerability","aliases":["CVE-2024-21413"],"related":[],"title":"Microsoft Outlook Remote Code Execution Vulnerability","description":"Microsoft Outlook contains an improper input validation vulnerability that allows for remote code execution. Successful exploitation of this vulnerability would allow an attacker to bypass the Office Protected View and open in editing mode rather than protected mode.\n\nCISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.","summary":"Microsoft Outlook has an improper input validation flaw in how it handles links, which lets a crafted message bypass Office Protected View and open content in editing mode. The sources say the bug allows remote code execution and that it is being exploited in the wild.","severity":"critical","cvss":9.8,"epss":null,"exploited":true,"exploited_at":"2025-02-06T00:00:00+00:00","products":[{"name":"Microsoft Office Outlook","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft 365 apps","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft office 2016","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft office 2019","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft office long term servicing channel","fixed":[],"affected":"= 2021","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["exploited","microsoft-office","other","outlook","windows"],"not_affected_if":["unknown"],"how_to_check":null,"fix":"Apply mitigations per vendor instructions, or discontinue use of the product if mitigations are unavailable (per CISA required action).","status":"open","published_at":"2024-02-13T18:16:00+00:00","first_seen_at":"2026-10-23T19:11:51+00:00","triaged_at":"2026-10-23T20:52:32+00:00","updated_at":"2026-10-23T22:29:05+00:00","category":"other","confidence":0.6,"triage":{"at":"2026-10-23T20:52:32Z","model":"claude-haiku-5-5","output":{"fix":"Apply mitigations per vendor instructions, or discontinue use of the product if mitigations are unavailable (per CISA required action).","reach":"internet","impact":"high","summary":"Microsoft Outlook has an improper input validation flaw in how it handles links, which lets a crafted message bypass Office Protected View and open content in editing mode. The sources say the bug allows remote code execution and that it is being exploited in the wild.","category":"other","who_cares":["outlook","microsoft-office","windows"],"confidence":0.6,"needs_auth":"no","worst_case":"Attacker runs code on the victim's machine via a crafted Outlook message","analyst_note":"Pull the Microsoft security update guide entry for CVE-2024-21413 to get fixed build numbers, the exact Protected View bypass mechanism, and the detection steps the sources do not give.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["unknown"],"user_interaction":"yes","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.00045,"input_tokens":2655,"output_tokens":368,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2024':8A,11A '-21413':9A,12A '2016':21A '2019':24A '365':17A 'action':124C 'allow':71B,93C,104C 'appli':125C 'apps':18A 'attack':106C 'bug':70B 'bypass':56B,108C 'channel':30A 'cisa':122C 'code':4A,73B,96C 'contain':86C 'content':62B 'craft':54B 'cve':7A,10A 'discontinu':131C 'edit':64B,116C 'execut':5A,74B,97C 'exploit':31B,80B,99C 'flaw':45B 'handl':49B 'improp':42B,88C 'input':43B,89C 'instruct':129C 'let':52B 'link':50B 'long':27A 'messag':55B 'microsoft':1A,13A,16A,19A,22A,25A,33B,38B,84C 'microsoft-offic':32B 'mitig':126C,137C 'mode':65B,117C,121C 'offic':34B,57B,110C 'office':14A,20A,23A,26A 'open':61B,114C 'outlook':2A,15A,36B,39B,85C 'per':127C 'product':135C 'protect':58B,111C,120C 'rather':118C 'remot':3A,72B,95C 'requir':123C 'say':68B 'servicing':29A 'sourc':67B 'success':98C 'term':28A 'unavail':139C 'use':132C 'valid':44B,90C 'vendor':128C 'view':59B,112C 'vulner':6A,91C,102C 'wild':83B 'window':37B 'would':103C","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2024-02-13T18:16:00+00:00","kev":{"dateAdded":"2025-02-06","dueDate":"2025-02-27","requiredAction":"Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.","knownRansomwareCampaignUse":"Unknown"},"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvss_by":"secure@microsoft.com","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2024-21413","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2024-21413","severity":null,"published_at":"2025-02-06T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:51+00:00","fetched_at":"2026-10-25T11:39:14+00:00","note":null},{"source":"nvd","external_id":"CVE-2024-21413","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-21413","severity":null,"published_at":"2024-02-13T18:16:00+00:00","modified_at":"2026-08-10T16:18:51+00:00","first_seen_at":"2026-10-23T22:29:05+00:00","fetched_at":"2026-10-23T22:29:05+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"}