Vulnerability · Published Jun 18, 2026 · Assigned by VulnCheck
CVE-2026-54390JTL Shop < 5.7.2 Server-Side Template Injection via Smarty Renderer
Critical 9.8
In plain English
A critical-severity security flaw in JTL Shop from JTL Software. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 49% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.
Official description
JTL Shop versions 5.2.0 through 5.7.1 contains a server-side template injection vulnerability that allows unauthenticated attackers to inject malicious template syntax due to unsanitized user-supplied input passed to the Smarty template engine. Attackers can exploit this flaw to read sensitive server-side values such as database credentials and encryption keys, and on versions 5.4.0 through 5.7.1, leverage registered Smarty modifiers including unserialize and file_get_contents to write a webshell to the web root and execute arbitrary commands as the web server user.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| JTL Software | JTL Shop | 5.2.0 – before 5.4.05.4.0 – before 5.5.45.6.0 – before 5.6.25.7.0 – before 5.7.2 |
Weakness: CWE-1336 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- https://sansec.io/research/jtl-shop-ssti-rce technical-description
- https://forum.jtl-software.de/threads/jtl-shop-5-7-aktuell-5-7-2.246278/ release-notes, patch
- https://www.vulncheck.com/advisories/jtl-shop-server-side-template-injection-via-smarty-renderer third-party-advisory