CVE-2017-11357
CVE-2017-11357 is a security flaw in Telerik User Interface (UI) for ASP.NET AJAX. Attackers can run their own code on Telerik User Interface (UI) for ASP.NET AJAX. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 26 Jan 2023, and says ransomware gangs have used it.[1]
Telerik User Interface (UI) for ASP.NET AJAX is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Telerik has published a fix or advice.
Description
CISA calls it a UI for ASP.NET AJAX insecure direct object reference in Telerik User Interface (UI) for ASP.NET AJAX. In its words: “Telerik UI for ASP.NET AJAX contains an insecure direct object reference vulnerability in RadAsyncUpload that can result in file uploads in a limited location and/or remote code execution.”[1]
The underlying weakness is improper input validation (CWE-20), in MITRE’s list of common software weaknesses.[2]
It scores 9.8 out of 10 on the Common Vulnerability Scoring System, which rates it critical, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; Telerik’s advisory has them[3]. CISA names the product as Telerik User Interface (UI) for ASP.NET AJAX.
Most families won’t have Telerik User Interface (UI) for ASP.NET AJAX; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 26 Jan 2023, 1,982 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 16 Feb 2023 to fix it.[1] CISA says ransomware gangs have used it.
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 78%. That’s in the top 1% of the flaws it scores.[4]
CISA assesses it as automatable: attackers can run it against many targets at once.
CISA doesn’t say who was attacked, or how.
Fix
Telerik has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Check whether you use it.Telerik User Interface (UI) for ASP.NET AJAX is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed, or not in use. CISA gave US government agencies until 16 Feb 2023 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 9.8.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks, noting that ransomware gangs have used it.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 78%.[4] |
See also
Other Telerik User Interface (UI) for ASP.NET AJAX flaws
- CVE-2017-11317: UI for ASP.NET AJAX unrestricted file upload ·
Other improper input validation flaws
- CVE-2026-93952, Arista VeloCloud Orchestrator: improper input validation ·
- CVE-2019-1068, Microsoft SQL Server: remote code execution ·
- CVE-2026-12569, PTC Windchill and FlexPLM: improper input validation ·
- CVE-2026-34910, Ubiquiti UniFi OS: improper input validation ·
- CVE-2026-6973, Ivanti Endpoint Manager Mobile (EPMM): improper input validation ·
References
- ^ Cybersecurity and Infrastructure Security Agency. “Telerik UI for ASP.NET AJAX Insecure Direct Object Reference Vulnerability”. Known Exploited Vulnerabilities Catalog, added 26 Jan 2023.
- ^ National Institute of Standards and Technology. “CVE-2017-11357 Detail”. National Vulnerability Database, published 23 Aug 2017.
- ^ Telerik. Advisories and fixes: docs.telerik.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.777, percentile 99.6, 31 Oct 2026.
- CVE Program. “CVE-2017-11357”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.