{"id":"CVE-2019-18935","kind":"vulnerability","aliases":["CVE-2019-18935"],"related":[],"title":"Progress Telerik UI for ASP.NET AJAX: Progress Telerik UI for ASP.NET AJAX Deserialization of Untrusted Data Vulnerability","description":"Progress Telerik UI for ASP.NET AJAX through 2019.3.1023 contains a .NET deserialization vulnerability in the RadAsyncUpload function. This is exploitable when the encryption keys are known due to the presence of CVE-2017-11317 or CVE-2017-11357, or other means. Exploitation can result in remote code execution. (As of 2020.1.114, a default setting prevents the exploit. In 2019.3.1023, but not earlier versions, a non-default setting can prevent exploitation.)","summary":"Progress Telerik UI for ASP.NET AJAX deserializes untrusted data through the RadAsyncUpload control, letting an unauthenticated request run code on the server. The attacker gets code execution as the w3wp.exe IIS worker process, and CISA lists it as actively exploited, including in ransomware campaigns.","severity":"critical","cvss":9.8,"epss":0.99737,"exploited":true,"exploited_at":"2021-11-03T00:00:00+00:00","products":[{"name":"Progress Telerik UI for ASP.NET AJAX","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["asp.net","exploited","iis","package","ransomware","telerik","windows"],"not_affected_if":["no-telerik-ui","non-asp.net-stack"],"how_to_check":null,"fix":"Apply the vendor update from Progress per the CISA required action; the fixed version is not stated in the sources.","status":"open","published_at":"2019-12-11T13:15:11+00:00","first_seen_at":"2026-10-23T19:11:53+00:00","triaged_at":"2026-10-23T21:43:24+00:00","updated_at":"2026-10-23T21:57:34+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-10-23T21:43:24Z","model":"claude-haiku-5-5","output":{"fix":"Apply the vendor update from Progress per the CISA required action; the fixed version is not stated in the sources.\nunknown","reach":"internet","impact":"high","summary":"Progress Telerik UI for ASP.NET AJAX deserializes untrusted data through the RadAsyncUpload control, letting an unauthenticated request run code on the server. The attacker gets code execution as the w3wp.exe IIS worker process, and CISA lists it as actively exploited, including in ransomware campaigns.","category":"package","who_cares":["asp.net","telerik","iis","windows"],"confidence":0.7,"needs_auth":"unknown","worst_case":"Attacker runs code on the web server as w3wp.exe","analyst_note":"Find the fixed Telerik UI for ASP.NET AJAX version and the exact RadAsyncUpload trigger conditions in the Progress advisory; the sources here do not name them.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["no-telerik-ui","non-asp.net-stack"],"user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"critical"},"cost_usd":0.000491,"input_tokens":2896,"output_tokens":402,"severity_before":"unknown"},"analyst_status":"queued","analyst_note":"Find the fixed Telerik UI for ASP.NET AJAX version and the exact RadAsyncUpload trigger conditions in the Progress advisory; the sources here do not name them.","search":"'-11317':114C '-11357':118C '-18935':20A,23A '-2017':113C,117C '-2019':19A,22A '2019.3.1023':88C,139C '2020.1.114':131C 'activ':75B 'ajax':6A,12A,29A,42B,86C 'asp.net':5A,11A,28A,30B,41B,85C 'attack':60B 'campaign':80B 'cisa':71B 'code':55B,62B,127C 'contain':89C 'control':49B 'cve':18A,21A,112C,116C 'data':16A,45B 'default':133C,147C 'deseri':13A,43B,92C 'due':107C 'earlier':142C 'encrypt':103C 'execut':63B,128C 'exploit':31B,76B,100C,122C,137C,151C 'for':27A 'function':97C 'get':61B 'ii':32B,67B 'includ':77B 'key':104C 'known':106C 'let':50B 'list':72B 'mean':121C 'net':91C 'non':146C 'non-default':145C 'packag':33B 'presenc':110C 'prevent':135C,150C 'process':69B 'progress':1A,7A,24A,37B,81C 'radasyncupload':48B,96C 'ransomwar':34B,79B 'remot':126C 'request':53B 'result':124C 'run':54B 'server':58B 'set':134C,148C 'telerik':2A,8A,25A,35B,38B,82C 'ui':3A,9A,26A,39B,83C 'unauthent':52B 'untrust':15A,44B 'version':143C 'vulner':17A,93C 'w3wp.exe':66B 'window':36B 'worker':68B","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2019-12-11T13:15:11+00:00","kev":{"dateAdded":"2021-11-03","dueDate":"2022-05-03","requiredAction":"Apply updates per vendor instructions.","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":"nvd@nist.gov","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2019-18935","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2019-18935","severity":null,"published_at":"2021-11-03T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:53+00:00","fetched_at":"2026-10-25T15:39:44+00:00","note":null},{"source":"epss","external_id":"CVE-2019-18935","url":"https://api.first.org/data/v1/epss?cve=CVE-2019-18935","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-23T19:13:44+00:00","fetched_at":"2026-10-23T19:13:44+00:00","note":null},{"source":"nvd","external_id":"CVE-2019-18935","url":"https://nvd.nist.gov/vuln/detail/CVE-2019-18935","severity":null,"published_at":"2019-12-11T13:15:11+00:00","modified_at":"2026-06-17T02:25:36+00:00","first_seen_at":"2026-10-23T21:57:34+00:00","fetched_at":"2026-10-23T21:57:34+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"}