CVE-2026-40478 | BDVDB-2026-327607 Detail
thymeleafthymeleaf
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.
Impact#
Per CVSS v3.1: confidentiality impact high, integrity impact high, availability impact high. Attack vector: network.
Weaknesses#
References#
- https://github.com/thymeleaf/thymeleaf/security/advisories/GHSA-xjw8-8c5c-9r79
- 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
- https://access.redhat.com/errata/RHSA-2026:21772
Exploit#
No public exploit known
History#
- Version 1Record published in the CVE List.
- Version 2Most recent update recorded in the CVE List.