{"basis":"claimed","id":"CVE-2019-18935","name":"Progress Telerik UI for ASP.NET AJAX Deserialization of Untrusted Data Vulnerability","vendorProject":"Progress","product":"Telerik UI for ASP.NET AJAX","publishedAt":"2019-12-11","cvss":{"score":9.8,"severity":"CRITICAL","version":"3.1"},"exploited":{"kevAdded":"2021-11-03","dueDate":"2022-05-03","ransomware":true},"epss":{"score":0.99737,"percentile":0.99954,"date":"2026-11-02"},"coverage":{"cloudflare":{"status":"no_history","firstOn":null,"daysToRule":null},"aws":{"status":"none","firstOn":null,"daysToRule":null},"azure":{"status":"rule","firstOn":null,"daysToRule":null},"google":{"status":"no_history","firstOn":null,"daysToRule":null},"fastly":{"status":"no_history","firstOn":null,"daysToRule":null},"f5":{"status":"no_history","firstOn":null,"daysToRule":null},"akamai":{"status":"no_source","firstOn":null,"daysToRule":null},"crs":{"status":"no_history","firstOn":null,"daysToRule":null}},"title":null,"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.)","cwes":["CWE-502"],"vendors":[{"vendor":"cloudflare","status":"no_history","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"aws","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"azure","status":"rule","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[{"id":"3786985173f6a28dc9982b7734c03ff055a7e3efc016bed6be1a04cc895aed23","cve_id":"CVE-2019-18935","vendor":"azure","product":"Front Door WAF (DRS)","rule_id":"99001012","rule_name":"Attempted Telerik WebUI insecure deserialization exploitation CVE-2019-18935","change":"listed","default_action":null,"published_on":null,"source_url":"https://learn.microsoft.com/en-us/azure/web-application-firewall/afds/waf-front-door-drs","source_title":"Front Door WAF (DRS) rule groups and rules","excerpt":"Rule 99001012: Critical - 5 · 2 · Attempted Telerik WebUI insecure deserialization exploitation CVE-2019-18935","first_seen_at":"2026-11-02T21:00:19.031Z"},{"id":"28e7c9f076e9d09cfd931ffb7c442df00f4e720e8c9672f480b4add59517f3bf","cve_id":"CVE-2019-18935","vendor":"azure","product":"Application Gateway WAF (DRS/CRS)","rule_id":"99001012","rule_name":"Attempted Telerik WebUI insecure deserialization exploitation CVE-2019-18935","change":"listed","default_action":null,"published_on":null,"source_url":"https://learn.microsoft.com/en-us/azure/web-application-firewall/ag/application-gateway-crs-rulegroups-rules","source_title":"Application Gateway WAF (DRS/CRS) rule groups and rules","excerpt":"Rule 99001012: Critical - 5 · 2 · Attempted Telerik WebUI insecure deserialization exploitation CVE-2019-18935","first_seen_at":"2026-11-02T21:00:19.183Z"}]},{"vendor":"google","status":"no_history","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"fastly","status":"no_history","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"f5","status":"no_history","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"akamai","status":"no_source","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"crs","status":"no_history","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]}],"updatedAt":"2026-11-04T01:17:44.293Z","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","ssvc":{"exploitation":"active","automatable":"yes","technicalImpact":"total"},"kevAction":"Apply updates per vendor instructions.","kevNotes":"https://nvd.nist.gov/vuln/detail/CVE-2019-18935","references":[{"url":"https://www.telerik.com/support/whats-new/release-history","name":null,"tags":[]},{"url":"https://codewhitesec.blogspot.com/2019/02/telerik-revisited.html","name":null,"tags":[]},{"url":"https://www.telerik.com/support/kb/aspnet-ajax/details/allows-javascriptserializer-deserialization","name":null,"tags":[]},{"url":"https://github.com/bao7uo/RAU_crypto","name":null,"tags":[]},{"url":"https://know.bishopfox.com/research/cve-2019-18935-remote-code-execution-in-telerik-ui","name":null,"tags":[]},{"url":"https://github.com/noperator/CVE-2019-18935","name":null,"tags":[]},{"url":"http://packetstormsecurity.com/files/155720/Telerik-UI-Remote-Code-Execution.html","name":null,"tags":[]},{"url":"https://www.telerik.com/support/whats-new/aspnet-ajax/release-history/ui-for-asp-net-ajax-r1-2020-%28version-2020-1-114%29","name":null,"tags":[]},{"url":"http://packetstormsecurity.com/files/159653/Telerik-UI-ASP.NET-AJAX-RadAsyncUpload-Deserialization.html","name":null,"tags":[]},{"url":"https://www.bleepingcomputer.com/news/security/us-federal-agency-hacked-using-old-telerik-bug-to-steal-data/","name":null,"tags":[]}],"affected":[],"briefing":{"status":{"id":"known_exploited","label":"Known exploited"},"why":"CISA lists CVE-2019-18935 as exploited in the wild since 2021-11-03, including known use in ransomware campaigns. It is reachable over the network without credentials or any user interaction (CVSS 9.8). A Metasploit module exists, so exploitation needs no custom work.","who":"Teams running Progress Telerik UI for ASP.NET AJAX. Affected versions are in the vendor advisory. Prioritise internet-facing instances.","what_to_do":[{"text":"Apply the vendor's fix; the advisory lists the affected and fixed versions."},{"text":"CISA's required action: Apply updates per vendor instructions. US federal agencies must act by 2022-05-03."},{"text":"Review exposed instances for signs of compromise: it was exploited before many systems were patched, and a later patch does not undo access already gained."},{"text":"Keep a WAF rule in place while you patch: Microsoft Azure ships a rule you may need to switch on. A WAF rule reduces exposure; it does not replace the patch.","href":"#edge","linkText":"Edge coverage"},{"text":"Check which WAF sits in front of your site and whether it covers this CVE.","href":"#check","linkText":"Check your domain"}],"evidence":[{"heading":"CVE record","text":"CVSS 3.1 9.8 (critical). Weakness: CWE-502.","links":[{"label":"CVE-2019-18935","href":"https://www.cve.org/CVERecord?id=CVE-2019-18935"},{"label":"NVD","href":"https://nvd.nist.gov/vuln/detail/CVE-2019-18935"}]},{"heading":"Exploit evidence","text":"Metasploit has a module. Exploit-DB lists 1 exploit.","links":[{"label":"Metasploit: Telerik UI ASP.NET AJAX RadAsyncUpload Deserialization","href":"https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/windows/http/telerik_rau_deserialization.rb"},{"label":"Exploit-DB: Telerik UI - Remote Code Execution via Insecure Deserialization","href":"https://www.exploit-db.com/exploits/47793"}]},{"heading":"Seen exploited","text":"Claimed in 2 Telegram posts (unverified).","links":[]},{"heading":"CISA KEV","text":"Added 2021-11-03, federal due date 2022-05-03, known ransomware use (catalog 2026.11.03, checked 2026-11-04).","links":[{"label":"CISA KEV catalog","href":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2019-18935"}]},{"heading":"EPSS","text":"99.7% probability of exploitation activity in the next 30 days, higher than 99% of CVEs (2026-11-02).","links":[{"label":"FIRST EPSS","href":"https://api.first.org/data/v1/epss?cve=CVE-2019-18935"}]},{"heading":"WAF vendor statements","text":"Microsoft Azure names it in a changelog. Quotes and dates below.","links":[{"label":"Vendor statements","href":"#evidence"}]}],"agent_prompt":"Assess whether the infrastructure available to you is affected by CVE-2019-18935 (Progress Telerik UI for ASP.NET AJAX Deserialization of Untrusted Data Vulnerability). Perform a read-only assessment within your authorized access. Do not send exploit traffic, scan third-party systems, change configuration or restart services.\n\n1. Verify the CVE record at https://www.cve.org/CVERecord?id=CVE-2019-18935 and the vendor advisory. Establish affected and fixed versions, including vendor backports. Cite sources and retrieval dates; flag anything you cannot verify.\n2. Inventory deployments of Progress Telerik UI for ASP.NET AJAX: asset, environment, owner where known, installed version or build, and how you confirmed it (package metadata, a version endpoint, image tags). An image tag alone does not prove the running version.\n3. Identify which deployments are reachable from the internet or untrusted networks, and through which paths (direct origin, load balancer, CDN or WAF).\n4. Assess compensating controls separately from patch status. Current edge WAF coverage for this CVE: Microsoft Azure: rule exists, check whether it is enabled. Live data: https://cve.vigilbase.com/api/v1/cves/CVE-2019-18935. Check whether the rule is enabled and in block mode on each path, and whether any path bypasses the WAF. A WAF rule is not a patch.\n5. It is known exploited (CISA KEV): review logs on exposed instances for signs of exploitation before and after patching.\n\nReturn a short summary and a table: asset | version/build | assessment (affected, fixed, not applicable, unknown) | exposure | compensating control | evidence | next action. List what you could not assess and the access needed to resolve it. Do not infer absence of compromise from patch status or a lack of alerts.\n\nRemediation guidance: Apply the vendor's fix; the advisory lists the affected and fixed versions. CISA's required action: Apply updates per vendor instructions. US federal agencies must act by 2022-05-03.\nMore: https://cve.vigilbase.com/cve/CVE-2019-18935"},"measured":[],"sightings":{"honeypot":null,"catalog":null,"reports":[],"telegram":{"posts":2,"last":"2026-11-01"},"days":{"honeypot":[],"reports":[],"telegram":["2026-09-19","2026-11-01"]}},"social":{"total":0,"first_seen":null,"daily":[{"day":"2026-10-22","posts":0},{"day":"2026-10-23","posts":0},{"day":"2026-10-24","posts":0},{"day":"2026-10-25","posts":0},{"day":"2026-10-26","posts":0},{"day":"2026-10-27","posts":0},{"day":"2026-10-28","posts":0},{"day":"2026-10-29","posts":0},{"day":"2026-10-30","posts":0},{"day":"2026-10-31","posts":0},{"day":"2026-11-01","posts":0},{"day":"2026-11-02","posts":0},{"day":"2026-11-03","posts":0},{"day":"2026-11-04","posts":0}],"top_posts":[],"exploit_repositories":[]}}