Cyber Resilience

CVE-2026-54390

CriticalPublic PoC

Published: 18 June 2026

Published
18 June 2026
Modified
23 June 2026
KEV Added
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Patch
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CVSS Score v4 9.3 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0033 25.2th percentile
Risk Priority 70 floored blend · peak EPSS

Summary

CVE-2026-54390 is a critical-severity Improper Neutralization of Special Elements Used in a Template Engine (CWE-1336) vulnerability. Its CVSS base score is 9.3 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 25.2th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

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…

more

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.

CWE(s)
CWE-1336

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1505.003 Web Shell Persistence
Adversaries may backdoor web servers with web shells to establish persistent access to systems.
attack.mitre.org →
T1059 Command and Scripting Interpreter Execution
Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries.
attack.mitre.org →
T1552.001 Credentials In Files Credential Access
Adversaries may search local file systems and remote file shares for files containing insecurely stored credentials.
attack.mitre.org →
Why these techniques?

Direct unauthenticated exploitation of public-facing web app (T1190) via SSTI enables reading credentials (T1552.001), writing webshell (T1505.003), and arbitrary command execution (T1059).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

Affected Assets

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JTL Shop
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References