CVE-2026-40478

criticalpriority · act · 90OT risk · criticalEU KEV · CNWEPSS 0.012 · 68 %ileEURUUS
grimoire priorityP2 · Scheduled
Exploitable?
—
no known exploitation
Likely / severe?
1.20% (68th) EPSS
CVSS 9 · critical
Is it mine?
9 products
Check your exposure
Who says so?
5 sources
cnnvd · enisa_euvd · fstec_bdu · nvd

EU KEVflagged by CNWreported 2026-10-10patched 2026-04-15

EPSS · scored 2026-10-22

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.

01

cvss

Technical severity, 0–10. One row per scoring source.

9.1
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · high–critical · 8.5–9.1

v3.19criticalAV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU
v3.19.1criticalCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:Hsecondary · ENISA EU
v3.19criticalCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:Hsecondary · security-advisories@github.comexploitability 2.2 · impact 6
v3.18.5highCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:Hsecondaryexploitability 1.8 · impact 6
v3.19criticalCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:Hsecondary · OSV
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: no · Technical Impact: totalcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-1336USCWE-1336USCWE-1336USCWE-917USCWE-917USCWE-917US
04

affected products (9)

Products and version ranges known to be affected.

05

advisories (1)

Vendor and ecosystem advisories describing this.

  • GHSA-xjw8-8c5c-9r79Improper neutralization of specific syntax patterns for unauthorized expressions in Thymeleaf2026-04-15ghsa · osvUS

    ### Impact A security bypass vulnerability exists in the expression execution mechanisms of Thymeleaf up to and including 3.1.3.RELEASE. 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). ### Patches This has been fixed in Thymeleaf 3.1.4.RELEASE. ### Workarounds No workaround is available beyond ensuring applications do not pass unvalidated user input directly to the template engine. Upgrading to 3.1.4.RELEASE is strongly recommended in any case. ### Credits Thanks to Dawid Bakaj (VIPentest.com) for responsible disclosure.

06

also known as (5)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

cnnvdenisa_euvdfstec_bdunvdosvNVDCVE.orgMITRE
published 2026-04-17modified 2026-08-18
08

references (8)

External citations — patches, advisories, analysis.

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