{"id":"CVE-2023-29357","kind":"vulnerability","aliases":["CVE-2023-29357"],"related":[],"title":"Microsoft SharePoint Server Elevation of Privilege Vulnerability","description":"Microsoft SharePoint Server contains an unspecified vulnerability that allows an unauthenticated attacker, who has gained access to spoofed JWT authentication tokens, to use them for executing a network attack. This attack bypasses authentication, enabling the attacker to gain administrator privileges.\n\nCISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.","summary":"Microsoft SharePoint Server accepts spoofed JWT authentication tokens, so a network attacker can bypass authentication. The attacker gets administrator privileges on the server.","severity":"critical","cvss":9.8,"epss":null,"exploited":true,"exploited_at":"2024-01-10T00:00:00+00:00","products":[{"name":"Microsoft SharePoint Server","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft sharepoint server","fixed":[],"affected":"= 2019","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["exploited","infrastructure","ransomware","self-hosted","sharepoint-server","windows"],"not_affected_if":["managed-hosting","sharepoint-online"],"how_to_check":null,"fix":"Apply the Microsoft mitigations for CVE-2023-29357 per vendor instructions, or stop using the affected SharePoint Server if mitigations are unavailable (CISA required action).","status":"open","published_at":"2023-06-14T00:15:09+00:00","first_seen_at":"2026-10-23T19:11:51+00:00","triaged_at":"2026-10-23T21:02:30+00:00","updated_at":"2026-10-23T22:29:05+00:00","category":"infrastructure","confidence":0.7,"triage":{"at":"2026-10-23T21:02:30Z","model":"claude-haiku-5-5","output":{"fix":"Apply the Microsoft mitigations for CVE-2023-29357 per vendor instructions, or stop using the affected SharePoint Server if mitigations are unavailable (CISA required action).","reach":"network","impact":"high","summary":"Microsoft SharePoint Server accepts spoofed JWT authentication tokens, so a network attacker can bypass authentication. The attacker gets administrator privileges on the server.","category":"infrastructure","who_cares":["sharepoint-server","self-hosted","windows"],"confidence":0.7,"needs_auth":"no","worst_case":"Unauthenticated attacker gains administrator privileges on SharePoint Server over the network","analyst_note":"Sources do not list affected or fixed versions or the Microsoft advisory; find the MSRC advisory for CVE-2023-29357 to get version ranges, patch names and detection steps.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["sharepoint-online","managed-hosting"],"user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"critical"},"cost_usd":0.00048,"input_tokens":2873,"output_tokens":386,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2023':9A,12A '-29357':10A,13A 'accept':33B 'access':68C 'action':95C 'administr':48B,91C 'allow':61C 'appli':96C 'attack':41B,46B,64C,81C,83C,88C 'authent':36B,44B,72C,85C 'bypass':43B,84C 'cisa':93C 'contain':56C 'cve':8A,11A 'discontinu':102C 'elev':4A 'enabl':86C 'execut':78C 'exploit':20B 'gain':67C,90C 'get':47B 'host':25B 'infrastructur':21B 'instruct':100C 'jwt':35B,71C 'microsoft':1A,14A,17A,30B,53C 'mitig':97C,108C 'network':40B,80C 'per':98C 'privileg':6A,49B,92C 'product':106C 'ransomwar':22B 'requir':94C 'self':24B 'self-host':23B 'server':3A,16A,19A,28B,32B,52B,55C 'sharepoint':2A,15A,18A,27B,31B,54C 'sharepoint-serv':26B 'spoof':34B,70C 'token':37B,73C 'unauthent':63C 'unavail':110C 'unspecifi':58C 'use':75C,103C 'vendor':99C 'vulner':7A,59C 'window':29B","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2023-06-14T00:15:09+00:00","kev":{"dateAdded":"2024-01-10","dueDate":"2024-01-31","requiredAction":"Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.","knownRansomwareCampaignUse":"Known"},"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-2023-29357","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2023-29357","severity":null,"published_at":"2024-01-10T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:51+00:00","fetched_at":"2026-10-25T10:39:05+00:00","note":null},{"source":"nvd","external_id":"CVE-2023-29357","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-29357","severity":null,"published_at":"2023-06-14T00:15:09+00:00","modified_at":"2026-06-17T05:49:52+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"}