Improper restriction of the scope of accessible objects in Thymeleaf expressions
Summary
| CVE | CVE-2026-40477 |
|---|---|
| State | PUBLISHED |
| Assigner | GitHub_M |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-04-17 22:16:33 UTC |
| Updated | 2026-07-15 02:21:06 UTC |
| 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 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. |
Risk And Classification
Primary CVSS: v3.1 8.5 HIGH from ADP
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
EPSS: 0.008620000 probability, percentile 0.544850000 (date 2026-07-18)
Problem Types: CWE-917 | CWE-1336 | CWE-917 CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection') | CWE-1336 CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine | CWE-917 Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | ADP | CVSS | 8.5 | HIGH | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H |
| 3.1 | [email protected] | Secondary | 9 | CRITICAL | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H |
| 3.1 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | Secondary | 8.5 | HIGH | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H |
| 3.1 | CNA | DECLARED | 9.1 | CRITICAL | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H |
CVSS v3.1 Breakdown
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
NVD Known Affected Configurations (CPE 2.3)
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/thymeleaf/thymeleaf/security/advisories/GHSA-r4v4-5mwr-2fwr | [email protected] | github.com | Vendor Advisory |
| bugzilla.redhat.com/show_bug.cgi | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | bugzilla.redhat.com | |
| security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40477.json | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | security.access.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-40477 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:21772 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| ADP | 2026-04-17T23:00:52.793Z | Reported to Red Hat. |
| ADP | 2026-04-17T21:53:47.271Z | Made public. |
Solutions
ADP: RHSA-2026:21772: Red Hat OpenShift Dev Spaces 3.28
Workarounds
ADP: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.