Threats / Progress / CVE-2019-18935
CVE-2019-18935
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Progress Telerik UI for ASP.NET AJAX vulnerability
Progress Telerik UI for ASP.NET AJAX contains a deserialization vulnerability in RadAsyncUpload that allows remote code execution on the server.
Verdict
Today item, not a backlog item.
Unauthenticated attackers can exploit unsafe deserialization of untrusted data through the RadAsyncUpload component to achieve arbitrary code execution in the w3wp.exe process context, enabling full server compromise.
CISA KEV Yes · 2021-11-033Ransomware use Flagged3EPSS 0.99737 (verify live)4Exploit Weaponized · public PoC5
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Fully weaponized — public exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
469 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), flagged for known ransomware use.
Probability (EPSS)
EPSS 0.99737 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Progress, Telerik UI for ASP.NET AJAX. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-502 Deserialization of Untrusted Data — weakness family: Injection.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malicious serialized object and send it to the RadAsyncUpload endpoint without authentication.
Business
The application accepts and processes untrusted input without validation, creating an entry point for attackers.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I trigger unsafe deserialization of my payload, which instantiates arbitrary .NET objects during the deserialization process.
Business
The deserialization mechanism executes attacker-controlled code during object reconstruction, bypassing application logic.
3
Lateral reach — past segmentation narrative 3
Attacker
I achieve remote code execution within the w3wp.exe process with the privileges of the application pool identity.
Business
The server is fully compromised; attackers can steal data, deploy ransomware, establish persistence, or pivot to internal systems.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05