CVE-2026-41901: Sandboxed Thymeleaf expressions vulnerable to improper recognition of unauthorized syntax patterns
Impact A security bypass vulnerability exists in the expression execution mechanisms of Thymeleaf up to and including 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.
Published May 4, 2026 · Updated May 13, 2026
Affected packages
org.thymeleaf:thymeleaf
- Ecosystem
- Maven
- Affected
- <= 3.1.4.RELEASE
- Fixed in
- 3.1.5.RELEASE
- Check
mvn dependency:tree -Dincludes=org.thymeleaf:thymeleaf
org.thymeleaf:thymeleaf-spring5
- Ecosystem
- Maven
- Affected
- <= 3.1.4.RELEASE
- Fixed in
- 3.1.5.RELEASE
- Check
mvn dependency:tree -Dincludes=org.thymeleaf:thymeleaf-spring5
org.thymeleaf:thymeleaf-spring6
- Ecosystem
- Maven
- Affected
- <= 3.1.4.RELEASE
- Fixed in
- 3.1.5.RELEASE
- Check
mvn dependency:tree -Dincludes=org.thymeleaf:thymeleaf-spring6
Advisory details
From the GitHub Advisory Database (CC BY 4.0).
Impact
A security bypass vulnerability exists in the expression execution mechanisms of Thymeleaf up to and including 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).
Patches
This has been fixed in Thymeleaf 3.1.5.RELEASE. All users are advised to upgrade immediately.
Workarounds
No workaround is available beyond ensuring applications do not pass unvalidated/unsanitized data directly to the template engine. Upgrading to 3.1.5.RELEASE is strongly recommended in any case.
Credited to cristianstaicu.
References
How this page is made: the data panel comes from the GitHub Advisory Database, CISA’s KEV catalog, the NVD and FIRST EPSS, and updates twice a day. No analysis has been written for this entry yet. Methodology