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Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')

CVE-2026-41901

High
9/10

Summary

A security bypass vulnerability exists in the expression execution mechanisms of Thymeleaf through 3.1.4.RELEASE. Although the library provides mechanisms to avoid the execution of potentially dangerous expressions in some specific sandboxed (restricted) contexts, it fails to properly neutralize specific constructs that allow this kind of expressions to be executed. If an application developer passes to the template engine unsanitized variables that contain such expressions, and these values are used in sandboxed contexts inside the templates, these expressions can be executed achieving Server-Side Template Injection (SSTI).

  • HIGH
  • NETWORK
  • HIGH
  • CHANGED
  • NONE
  • NONE
  • HIGH
  • HIGH

CWE-917 - Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')

The software constructs all or part of an expression language (EL) statement in a framework such as a Java Server Page (JSP) using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended EL statement before it is executed.

References

Advisory Timeline

  • Published