Vulnerability Details 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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.001
EPSS Ranking 15.8%
CVSS Severity
CVSS v3 Score 9.0
Products affected by CVE-2026-40478
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cpe:2.3:a:thymeleaf:thymeleaf:-
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cpe:2.3:a:thymeleaf:thymeleaf:1.1.5
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.0
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.1
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.10
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.11
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.12
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.13
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.14
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.15
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.16
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.17
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.18
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.19
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.2
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.20
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.21
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.3
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.4
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.5
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.6
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.7
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.8
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cpe:2.3:a:thymeleaf:thymeleaf:2.0.9
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cpe:2.3:a:thymeleaf:thymeleaf:2.1.0
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cpe:2.3:a:thymeleaf:thymeleaf:2.1.1
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cpe:2.3:a:thymeleaf:thymeleaf:2.1.2
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cpe:2.3:a:thymeleaf:thymeleaf:2.1.3
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cpe:2.3:a:thymeleaf:thymeleaf:2.1.4
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cpe:2.3:a:thymeleaf:thymeleaf:2.1.5
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cpe:2.3:a:thymeleaf:thymeleaf:2.1.6
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cpe:2.3:a:thymeleaf:thymeleaf:3.0.0
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cpe:2.3:a:thymeleaf:thymeleaf:3.0.1
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cpe:2.3:a:thymeleaf:thymeleaf:3.0.10
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cpe:2.3:a:thymeleaf:thymeleaf:3.0.11
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cpe:2.3:a:thymeleaf:thymeleaf:3.0.12
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cpe:2.3:a:thymeleaf:thymeleaf:3.0.2
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cpe:2.3:a:thymeleaf:thymeleaf:3.0.3
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cpe:2.3:a:thymeleaf:thymeleaf:3.0.4
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cpe:2.3:a:thymeleaf:thymeleaf:3.0.5
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cpe:2.3:a:thymeleaf:thymeleaf:3.0.6
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cpe:2.3:a:thymeleaf:thymeleaf:3.0.7
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cpe:2.3:a:thymeleaf:thymeleaf:3.0.8
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cpe:2.3:a:thymeleaf:thymeleaf:3.0.9
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cpe:2.3:a:thymeleaf:thymeleaf:3.1.1
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cpe:2.3:a:thymeleaf:thymeleaf:3.1.2
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cpe:2.3:a:thymeleaf:thymeleaf:3.1.3