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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 16 Feb 2023. Known ransomware use
Telerik Ui For Asp.net AjaxApplication · Progress

CVE-2017-11357

CRITICAL · 9.8 CVSS v3.1 Published 2017-08-23
Fix available
A fix is available. Upgrade to 2020.1.114 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild Ransomware High EPSS Public exploit Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Progress Telerik UI for ASP.NET AJAX before R2 2017 SP2 does not properly restrict user input to RadAsyncUpload, which allows remote attackers to perform arbitrary file uploads or execute arbitrary code.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Progress Telerik UI for ASP.NET AJAX before R2 2017 SP2 contains a file upload vulnerability in the RadAsyncUpload component that improperly restricts user input, allowing remote attackers to upload arbitrary files and potentially execute arbitrary code on the server.

MitigationUpgrade to Telerik UI for ASP.NET AJAX R2 2017 SP2 or later. If immediate upgrade is not feasible, implement strict file type validation and authentication on RadAsyncUpload endpoints, and consider disabling the component until a patch can be applied.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Telerik Ui For Asp.net AjaxApplication
Affected:< 2020.1.114

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the installed Telerik UI for ASP.NET AJAX version
    Locate the Telerik.Web.UI.dll file in the application's bin directory and check its assembly version property, or look for version information in the web.config assembly binding section if present
    Affected if The discovered version number is lower than 2020.1.114
  2. Confirm RadAsyncUpload component is in use
    Search the application codebase for references to RadAsyncUpload in .aspx pages, .ascx user controls, or code-behind files
    Affected if RadAsyncUpload is actively used within the application
  3. Inspect web.config for RadAsyncUpload handler configuration
    Examine the web.config file for Telerik.Web.UI.AsyncUploadHandler, RadAsyncUpload configuration entries, and custom handler mappings
    Affected if The handler is configured and accessible without proper restrictions
  4. Verify file type validation settings for upload functionality
    Check the RadAsyncUpload configuration for allowed extensions, max file size limits, and whether upload restrictions are enforced
    Affected if File type validation is missing, weak, or can be bypassed
  5. Check if upload handlers are publicly accessible
    Review IIS configuration and web.config to determine if Telerik upload handlers such as Telerik.Web.UI.DialogHandler.aspx and Telerik.Web.UI.AsyncUploadHandler are exposed to unauthenticated users
    Affected if Upload handlers are accessible without authentication or authorization controls

A user is affected if their Telerik UI for ASP.NET AJAX version is below 2020.1.114 and RadAsyncUpload is enabled with accessible upload handlers.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2020.1.114 or later
Fixed in 2020.1.114
Interim mitigation

Upgrade to Telerik UI for ASP.NET AJAX R2 2017 SP2 or later. If immediate upgrade is not feasible, implement strict file type validation and authentication on RadAsyncUpload endpoints, and consider disabling the component until a patch can be applied.

Recommended fix High confidence

Telerik UI for ASP.NET AJAX version 2020.1.114 or later (R2 2017 SP2 and subsequent releases contain the fix)

  1. 1. Identify the current version of Telerik UI for ASP.NET AJAX in use by checking the bin folder for Telerik.Web.UI.dll version or reviewing project references
  2. 2. Download the latest version of Telerik UI for ASP.NET AJAX from the official Telerik website (www.telerik.com)
  3. 3. Backup the current project and all related assemblies before making changes
  4. 4. Replace the existing Telerik.Web.UI.dll with the version from 2020.1.114 or later
  5. 5. Rebuild and redeploy the application
  6. 6. Verify that RadAsyncUpload functionality works correctly after the upgrade
  7. 7. Scan for any other vulnerable instances of Telerik UI for ASP.NET AJAX in the environment
Caveat Minor: Ensure custom handlers and configuration for RadAsyncUpload are compatible with newer versions; test thoroughly in non-production first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Telerik Ui For Asp.net Ajax Exploited in the wild — priority engagement
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing10.0 h
  • Review / QA6.0 h
34.0 hours of engineering $5,940
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2017-11357 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data