CVE-2026-40478

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.

• CWE-917
• CWE-1336
• CWE-917

• https://github.com/thymeleaf/thymeleaf/security/advisories/GHSA-xjw8-8c5c-9r79Vendor Advisory
• https://access.redhat.com/errata/RHSA-2026:21772
• https://access.redhat.com/security/cve/CVE-2026-40478
• https://bugzilla.redhat.com/show_bug.cgi?id=2459349
• https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40478.json

Published

Apr 17, 2026

Last Modified

Aug 4, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-40471hackage-server lacked Cross-Site Request Forgery (CSRF) prot…9.6
• CVE-2026-40472In hackage-server, user-controlled metadata from .cabal file…9.9
• CVE-2026-40473The camel-mina component's MinaConverter.toObjectInput(IoBuf…8.8
• CVE-2026-40474wger is a free, open-source workout and fitness manager. In …7.6
• CVE-2026-40476graphql-go is a Go implementation of GraphQL. In versions 15…7.5
• CVE-2026-40477Thymeleaf is a server-side Java template engine for web and …9
• CVE-2026-40479Kimai is an open-source time tracking application. In versio…5.4
• CVE-2026-4048OS Command Injection Remote Code Execution Vulnerability in …7.2
• CVE-2026-40480ChurchCRM is an open-source church management system. In ver…7.1
• CVE-2026-40481monetr is a budgeting application for recurring expenses. In…7.5
• CVE-2026-40482ChurchCRM is an open-source church management system. Versio…7.1
• CVE-2026-40483ChurchCRM is an open-source church management system. In ver…5.4