CVE-2026-41901

Critical

Description

Thymeleaf is a server-side Java template engine for web and standalone environments. Prior to 3.1.5.RELEASE, a security bypass vulnerability exists in the expression execution mechanisms of Thymeleaf. 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). This vulnerability is fixed in 3.1.5.RELEASE.

SeverityCritical
CVSS9.0
Exploit probability—
ProductOrg.thymeleaf:thymeleaf
PublishedMay 12, 2026
First seenMay 12, 2026

How to fix

Update
  • org.thymeleaf:thymeleaf3.1.5.RELEASE or later
  • org.thymeleaf:thymeleaf-spring53.1.5.RELEASE or later
  • org.thymeleaf:thymeleaf-spring63.1.5.RELEASE or later

Affected products

ProductAffected versionsFixed in
org.thymeleaf:thymeleafMavenv < 3.1.5.RELEASE3.1.5.RELEASE
org.thymeleaf:thymeleaf-spring5Mavenv < 3.1.5.RELEASE3.1.5.RELEASE
org.thymeleaf:thymeleaf-spring6Mavenv < 3.1.5.RELEASE3.1.5.RELEASE

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CVE-2026-41901 · Org.thymeleaf:thymeleaf · Dark Radar