CVE-2026-41901
Description
A flaw was found in Thymeleaf, a server-side Java template engine. A security bypass vulnerability exists in its expression execution mechanisms, allowing specific constructs to be executed even in restricted sandboxed contexts. If an application developer passes unsanitized variables containing malicious expressions to the template engine, a remote attacker could exploit this to achieve Server-Side Template Injection (SSTI), potentially leading to arbitrary code execution.
Statement
This is an Important security bypass in Thymeleaf's expression execution, allowing Server-Side Template Injection (SSTI). The flaw enables arbitrary code execution if an application processes unsanitized input containing malicious expressions within sandboxed template contexts.
Red Hat OpenShift Dev Spaces is not affected by this vulnerability as each version ships with a patched version of Thymeleaf 3.1.5.RELEASE. Thymeleaf is only used in Red Hat OpenShift Dev Spaces for email generation rather than web request handling which limits the severity of this vulnerability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 9 | N/A | 9 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Changed | N/A | Changed |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data
Integrity
Technical Impact: Execute Unauthorized Code or Commands
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