CVE
Progress Telerik UI for WinForms arbitrary protocol handler launch via document hyperlinks
Affects Telerik UI for WinForms from 2026.3.1007 before 2026.4.1111. Fixed in 2026.4.1111.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 2026.4.1111
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. Telerik UI for WinForms versions prior to 2026.4.1111
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- FIRST's estimate of the chance attackers exploit it in the next 30 days, updated daily.What do these mean? →
- 0.11% · 1st percentile
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 13/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Progress Software's Telerik UI for WinForms has an untrusted URL redirection flaw that lets an attacker launch arbitrary operating system protocol handlers with attacker-controlled arguments. The attacker must act locally, and the attack works only if a user opens a crafted document or hyperlink that uses a non-allowlisted URI scheme.
Read the original description
In Telerik UI for WinForms, versions prior to 2026.4.1111, an untrusted URL redirection vulnerability exists that allows an attacker to launch arbitrary operating system protocol handlers with attacker-controlled arguments via crafted documents and hyperlinks with a non-allowlisted URI scheme that the user opens.
Who should check
Teams shipping or running Telerik UI for WinForms desktop apps on versions before 2026.4.1111, where users open crafted documents or hyperlinks.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure5/25Specific setups only
- Reach?/20Unknown. No tracked technology or package matched
- Severity7.8/10CVSS 7.8
- No patch0/5No signal
What would change the score
- Would score about 63 if added to CISA KEV
- Would score about 58 if CISA's SSVC rates exploitation active
- Would score about 23 if CISA's SSVC rates it automatable
What to do
Check whether your setup matches what the bug needs.
Telerik UI for WinForms versions prior to 2026.4.1111Upgrade to a fixed version: 2026.4.1111.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-124700 (URL Redirection to Untrusted Site in Progress Telerik UI for WinForms), using the cve.now data below.
Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.
What cve.now has for CVE-2026-124700 (entry last updated 2026-11-12):
Affected:
- Progress Software Telerik UI for WinForms: from 2026.3.1007, fixed in 2026.4.1111
Fixed versions: 2026.4.1111.
Conditions (all must be true for the bug to be hit):
- Telerik UI for WinForms versions prior to 2026.4.1111 (source: https://www.telerik.com/products/winforms/documentation/knowledge-base/kb-security-untrusted-url-redirection-cve-2026-124700)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: local access, no login, a user action.
CISA KEV: CVE-2026-124700 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-124700 only. If you also check another CVE, look up its own KEV status; never assume it from this one.
How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.
Verify against the linked advisories before concluding, and cite the date you read each one:
- https://www.telerik.com/products/winforms/documentation/knowledge-base/kb-security-untrusted-url-redirection-cve-2026-124700
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.
Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.
Entry: https://cve.now/CVE-2026-124700
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-124700"}.Timeline
- CVE published
- First seen by cve.now
Affected versions
- Progress Software Telerik UI for WinForms
From 2026.3.1007 · fixed in 2026.4.1111
Evidence 3
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Advisory
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-124700
Is CVE-2026-124700 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
The advisory title describes URL redirection to an untrusted site, meaning the product can send users to a web address that is not trusted. The checked facts do not give further detail on how this happens.Source: telerik.com
Which versions are affected by CVE-2026-124700?
Telerik UI for WinForms: from 2026.3.1007 before 2026.4.1111.Source: cve.now feed data
Am I affected, and how do I check?
Telerik UI for WinForms versions from 2026.3.1007 up to, but not including, 2026.4.1111 are in the affected range. To check a project, look at the Telerik UI for WinForms version referenced in the project or its NuGet package settings.Source: telerik.com
How do I fix CVE-2026-124700?
Upgrade Telerik UI for WinForms to 2026.4.1111 or later, which is the fixed version listed for this vulnerability.Source: telerik.com