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NVD / CVE Program· CNA mitre

CVE-2021-28141: An issue was discovered in Progress Telerik UI for ASP.NET AJAX 2021.1.224.

Noroxi assessment

Priority: Plan (action score 40/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 2.3% (FIRST EPSS); higher than 83.4% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to the record, no fixed version is available yet.

Add it to your regular patch cycle. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

An issue was discovered in Progress Telerik UI for ASP.NET AJAX 2021.1.224. It allows unauthorized access to MicrosoftAjax.js through the Telerik.Web.UI.WebResource.axd file. This may allow the attacker to gain unauthorized access to the server and execute code. To exploit, one must use the parameter _TSM_HiddenField_ and inject a command at the end of the URI. NOTE: the vendor states that this is not a vulnerability. The request's output does not indicate that a "true" command was executed on the server, and the request's output does not leak any private source code or data from the server

CriticalCVSS 9.8 · v3.1—No exploit No fix recorded
Published
Mar 11, 2021
Updated
Jun 16, 2026
EPSS
2.3% · 83th percentile

Report tools

JSON

Action score

40

Plan

Add it to your regular patch cycle.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 2.3%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-28141

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
progresstelerik ui for asp.net ajax

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • progress telerik ui for asp.net ajax2021.1.224

Same product

progress: all records

Other highest-scoring records for the same primary product.

  • CVE-2017-11357Progress Telerik UI for ASP.NET AJAX before R2 2017 SP2 does not properly restrict user input to RadAsyncUpload, which allows remote attackeKEV
    92Now
  • CVE-2026-6023Deserialization of Untrusted Data Vulnerability in Telerik UI for ASP.NET AJAX
    39Monitor
  • CVE-2025-3600Unsafe Reflection Vulnerability in Telerik UI for ASP.NET AJAX
    38Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2014-2217Dec 25, 2014 · Absolute path traversal vulnerability in the RadAsyncUpload control in the RadControls in Telerik UI for ASP.NET AJAX before Q3 2012 SP2 all
    31Monitor
  • Later →CVE-2026-2878Feb 25, 2026 · Insufficient Entropy Vulnerability in Telerik UI for ASP.NET AJAX
    23Monitor
  • Later →CVE-2026-6022Apr 22, 2026 · Uncontrolled Resource Consumption Vulnerability in Telerik UI for ASP.NET AJAX
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-862 · Missing Authorization

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

All records