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Description

Thymeleaf is a server-side Java template engine for web and standalone environments. Versions 3.1.3.RELEASE and prior contain a security bypass vulnerability in the the expression execution mechanisms. Although the library provides mechanisms to prevent expression injection, it fails to properly neutralize specific syntax patterns that allow for the execution of unauthorized expressions. If an application developer passes unvalidated user input directly to the template engine, an unauthenticated remote attacker can bypass the library's protections to achieve Server-Side Template Injection (SSTI). This issue has ben fixed in version 3.1.4.RELEASE.

PUBLISHED Reserved 2026-04-13 | Published 2026-04-17 | Updated 2026-04-17 | Assigner GitHub_M




CRITICAL: 9.1CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Problem types

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

CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine

Product status

< 3.1.4.RELEASE
affected

< 3.1.4.RELEASE
affected

< 3.1.4.RELEASE
affected

References

github.com/...meleaf/security/advisories/GHSA-xjw8-8c5c-9r79

cve.org (CVE-2026-40478)

nvd.nist.gov (CVE-2026-40478)

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