Unauthenticated code execution via email subject template injection
Published Jun 18, 2026 · Updated Jun 18, 2026
Server-side template injection in JTL-Shop 5.2.0 through 5.7.1 allows remote attackers to read secrets and, on later versions, execute code. The email subject renderer passes unsanitized user-controlled syntax to Smarty, which evaluates it as a template instead of treating it as text. Unauthenticated access exposes credentials on all affected versions; versions 5.4.0 through 5.7.1 also register modifiers that enable webshell writes and commands as the web server user.
Summary
What happened
Server-side template injection in JTL-Shop 5.2.0 through 5.7.1 allows remote attackers to read secrets and, on later versions, execute code. The email subject renderer passes unsanitized user-controlled syntax to Smarty, which evaluates it as a template instead of treating it as text. Unauthenticated access exposes credentials on all affected versions; versions 5.4.0 through 5.7.1 also register modifiers that enable webshell writes and commands as the web server user.
The record
- CVE
- CVE-2026-54390
- Published
- Jun 18, 2026
- Updated
- Jun 18, 2026
- Vendor
- JTL-Software
- Product
- JTL-Shop
- Classifications
- CWE-1336, T1190, T1505.003
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 18, 2026CVE publishedPublication date reported by the CVE source.
- Jun 18, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=5.2.0 <=5.3.x
- Affected versionversion=5.4.0 <=5.7.1
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Reported exploitation
- Active exploitation of JTL-Shop email-subject SSTIreported exploitation
Technologies
Your stack
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Your stack
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