Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Remote unauthenticated handler with no user interaction gives AV:N/AC:L/PR:N/UI:N; impact is information disclosure/SSRF only, so C:H with I:N/A:N and unchanged scope.
Primary rating from Vendor (ProgressSoftware).
CVSS VectorVendor: ProgressSoftware
Lifecycle Timeline
3DescriptionCVE.org
In Progress® Telerik® UI for AJAX prior to v2026.2.708, insufficient validation of the language parameter in the spell check handler may allow an attacker to influence server-side file path resolution and trigger unintended server-side requests.
AnalysisAI
Server-side file path manipulation and forced server-side requests in Progress Telerik UI for ASP.NET AJAX before v2026.2.708 stem from insufficient validation of the language (DictionaryLanguage) parameter in the spell check handler, letting remote attackers coerce the server into resolving attacker-influenced file paths and issuing unintended outbound requests. Classified as information disclosure (CWE-36, absolute path traversal) with a CVSS 7.5 confidentiality-only impact, it exposes sensitive server-side file contents. No public exploit identified at time of analysis, and it is not listed in CISA KEV.
Technical ContextAI
Telerik UI for ASP.NET AJAX is a widely used commercial suite of server-side web controls (RadEditor, RadSpell, RadAsyncUpload, etc.) embedded in .NET web applications, historically a high-value target for path and deserialization flaws. The affected component is the spell check handler (RadSpell/spell check dialog), which accepts a DictionaryLanguage/language parameter used to locate the dictionary file on the server. CWE-36 (Absolute Path Traversal) is the root cause class: user-controlled input flows into a file path without adequate normalization or allow-listing, so the parameter can reference paths outside the intended dictionary directory and, per the advisory, can also steer the handler into making server-side requests (an SSRF-like secondary effect). The single affected CPE is cpe:2.3:a:progress_software:telerik_ui_for_asp.net_ajax.
RemediationAI
Vendor-released patch: v2026.2.708 - upgrade the Telerik UI for ASP.NET AJAX assemblies in all affected applications to v2026.2.708 or later as the primary fix, per the advisory at https://www.telerik.com/products/aspnet-ajax/documentation/knowledge-base/kb-security-spellchecker-dictionarylanguage-path-traversal-CVE-2026-13189. Where immediate patching is not possible, disable or remove the spell check (RadSpell) handler if the application does not use spell checking, or restrict access to the spell check endpoint via web server/WAF rules that reject requests supplying traversal-style or absolute-path values in the DictionaryLanguage/language parameter - noting these controls break legitimate multi-language spell checking and can be bypassed if filtering is incomplete. Additionally, apply egress network filtering from the web server to limit the impact of forced server-side requests, with the trade-off that overly strict outbound rules may disrupt legitimate integrations.
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Same weakness CWE-36 – Absolute Path Traversal
View allSame technique Information Disclosure
View allShare
External POC / Exploit Code
Leaving vuln.today
EUVD-2026-47694
GHSA-hh76-q7vh-vv92