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CVE-2026-13189 – SSRF via Path Traversal in Spell Check Handler – Telerik UI for ASP.NET AJAX pri…

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Summary

CVE-2026-13189 is a high-severity Server-Side Request Forgery (SSRF) vulnerability in Progress Telerik UI for ASP.NET AJAX, affecting all versions from 2011.2.712 through 2026.2.519 (prior to v2026.2.708). The flaw resides in the spell check handler’s DictionaryLanguage parameter, which lacks sufficient input validation, enabling unauthenticated remote attackers to influence server-side file path resolution and trigger unintended server-side network requests. With a CVSS v3.1 score of 7.5 (High) and no authentication or user interaction required, this vulnerability poses significant risk to any internet-exposed deployment.

Technical details

  • Root cause: Insufficient validation of the DictionaryLanguage (language) parameter in the RadSpell spell check HTTP handler (CWE-36: Absolute Path Traversal). The handler resolves file paths on the server based on the attacker-supplied language value without adequately sanitizing or restricting the input.
  • Trigger conditions: An attacker sends a crafted HTTP request to the spell check handler containing a manipulated language parameter. No authentication, privileges, or user interaction are required.
  • Attack vector: Remotely exploitable over the network (AV:N) with low attack complexity (AC:L), no privileges required (PR:N), and no user interaction (UI:N).
  • Impact: Successful exploitation allows the attacker to influence server-side file path resolution and initiate unintended server-side requests (SSRF), resulting in high confidentiality impact (C:H). Integrity and availability are not affected (I:N / A:N).

Affected software

  • Progress Telerik UI for ASP.NET AJAX — all versions from 2011.2.712 through 2026.2.519 (all releases prior to v2026.2.708)

Severity

  • CVSS v3.1 Base Score: 7.5 (High)
  • Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Mitigation and recommended actions

  • Immediate: Upgrade to Progress Telerik UI for ASP.NET AJAX v2026.2.708 (2026 Q2 SP1) or later, which contains the vendor-supplied fix for this vulnerability.
  • If immediate patching is not feasible, consider restricting network-level access to the spell check handler endpoint and applying web application firewall (WAF) rules to filter requests containing unsanitized language parameter values.

IONIX Status

The IONIX research team is tracking ongoing exploitation attempts and recommends immediate patching. Potentially affected assets are outlined in this post.

References

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1

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