CVE-2026-40477

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 expression execution mechanisms. Although the library provides mechanisms to prevent expression injection, it fails to properly restrict the scope of accessible objects, allowing specific potentially sensitive objects to be reached from within a template. 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.

CVSS v3 9.0 CRITICAL

9.0^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 2.2 / Impact : 6.0

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope CHANGED

References

Link	Resource
https://github.com/thymeleaf/thymeleaf/security/advisories/GHSA-r4v4-5mwr-2fwr	Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:21772
https://access.redhat.com/security/cve/CVE-2026-40477
https://bugzilla.redhat.com/show_bug.cgi?id=2459344
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40477.json

Configurations

Configuration 1 (hide)

cpe:2.3:a:thymeleaf:thymeleaf:*:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-04-17 22:16

Updated : 2026-08-04 13:18

NVD link : CVE-2026-40477

Mitre link : CVE-2026-40477

CVE.ORG link : CVE-2026-40477

JSON object : View

Products Affected

thymeleaf

thymeleaf

CWE

CWE-917

Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')

CWE-1336

Improper Neutralization of Special Elements Used in a Template Engine

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