Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
thymeleaf thymeleaf — Improper neutralization of specific syntax patterns for unauthorized expressions in Thymeleaf
AV AC PR UI S C I A CVSS EPSS %ile KEV
N H N N C H H H 9.0 .0077 52.7 —
AFFECTED
Product Versions Fixed
thymeleaf < 3.1.4.RELEASE – —
org.thymeleaf:thymeleaf-spring5 < 3.1.4.RELEASE – —
org.thymeleaf:thymeleaf-spring6 < 3.1.4.RELEASE – —
TIMELINE
Apr 13 Reserved by GitHub_M
Apr 17 Published (CNA: GitHub_M)
Aug 18 RESCORED — CVE-2026-40478 (thymeleaf). CVSS 9.1 → 9 (NVD).
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.
Lifecycle
Complete event history — 3 events, chronological
| Date | Event | Detail |
|---|
| April 13, 2026 | Reserved | Reserved by GitHub_M |
| April 17, 2026 | Published | Published (CNA: GitHub_M) |
| August 18, 2026 | RESCORED | RESCORED — CVE-2026-40478 (thymeleaf). CVSS 9.1 → 9 (NVD). |
Affected
Affected products and packages — 3 rows
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|
| thymeleaf | thymeleaf | — | < 3.1.4.RELEASE | — |
| thymeleaf | org.thymeleaf:thymeleaf-spring5 | — | < 3.1.4.RELEASE | — |
| thymeleaf | org.thymeleaf:thymeleaf-spring6 | — | < 3.1.4.RELEASE | — |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-40478 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.