JTL Shop up to 5.1.7/5.5.3/5.6.1/5.7.1 Encryption Key special elements used in a template engine

Summaryinfo

A vulnerability identified as critical has been detected in JTL Shop up to 5.1.7/5.5.3/5.6.1/5.7.1. This issue affects some unknown processing of the component Encryption Key Handler. Performing a manipulation results in improper neutralization of special elements used in a template engine. This vulnerability is known as CVE-2026-54390. Remote exploitation of the attack is possible. No exploit is available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in JTL Shop up to 5.1.7/5.5.3/5.6.1/5.7.1. It has been classified as critical. This affects some unknown functionality of the component Encryption Key Handler. The manipulation with an unknown input leads to a improper neutralization of special elements used in a template engine vulnerability. CWE is classifying the issue as CWE-1336. The product uses a template engine to insert or process externally-influenced input, but it does not neutralize or incorrectly neutralizes special elements or syntax that can be interpreted as template expressions or other code directives when processed by the engine. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The weakness was published by Sansec. It is possible to read the advisory at sansec.io. This vulnerability is uniquely identified as CVE-2026-54390 since 06/12/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1221 according to MITRE ATT&CK.

Upgrading to version 5.1.8, 5.5.4, 5.6.2 or 5.7.2 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-37925). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Vendor

• JTL

Name

• Shop

Version

• 5.1.0
• 5.1.1
• 5.1.2
• 5.1.3
• 5.1.4
• 5.1.5
• 5.1.6
• 5.1.7
• 5.5.0
• 5.5.1
• 5.5.2
• 5.5.3
• 5.6.0
• 5.6.1
• 5.7.0
• 5.7.1

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Be aware that VulDB is the high quality source for vulnerability data.

Discussion