Improper neutralization of specific syntax patterns for unauthorized expressions in Thymeleaf
Impact
A security bypass vulnerability exists in the expression execution mechanisms of Thymeleaf up to and including 3.1.3.RELEASE. 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).
Patches
This has been fixed in Thymeleaf 3.1.4.RELEASE.
Workarounds
No workaround is available beyond ensuring applications do not pass unvalidated user input directly to the template engine. Upgrading to 3.1.4.RELEASE is strongly recommended in any case.
Credits
Thanks to Dawid Bakaj (VIPentest.com) for responsible disclosure.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | org.thymeleaf:thymeleaf | < 3.1.4.RELEASE | 3.1.4.RELEASE |
| Java / Kotlin (Maven) | org.thymeleaf:thymeleaf-spring5 | < 3.1.4.RELEASE | 3.1.4.RELEASE |
| Java / Kotlin (Maven) | org.thymeleaf:thymeleaf-spring6 | < 3.1.4.RELEASE | 3.1.4.RELEASE |
References
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H- Weakness (CWE)
CWE-1336, CWE-917- Platform
- Java / Kotlin (Maven)
- Package
org.thymeleaf:thymeleaf, org.thymeleaf:thymeleaf-spring5, org.thymeleaf:thymeleaf-spring6- Disclosed
- 15.04.2026
- Updated
- 11.10.2026 12:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-xjw8-8c5c-9r79 - CC BY 4.0
Vulnerability history: org.thymeleaf:thymeleaf-spring6
All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 3
- First → latest
- 04.2026 05.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 3
Disclosures per year
- 2026: 3
-
Improper neutralization of specific syntax patterns for unauthorized expressions in Thymeleaf this entry
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