CVE-2026-73330 in CamaleonCMS
Summary
by MITRE • 08/12/2026
CamaleonCMS 2.9.1 contains a server-side template injection vulnerability that allows authenticated administrators to execute arbitrary commands by embedding ERB tags in the email parameter of the test_email settings action, which are evaluated when an SMTP rejection reflects the recipient address back in the exception message rendered as an inline ERB template. Attackers can submit a crafted email parameter containing ERB expressions through the admin settings test_email endpoint, causing the Rails inline template renderer to evaluate attacker-controlled Ruby code and achieve arbitrary command execution as the Rails process user.
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Analysis
by VulDB Data Team • 08/12/2026
This vulnerability exists within CamaleonCMS version 2.9.1 and represents a critical server-side template injection flaw that affects authenticated administrator users. The issue stems from improper input validation and sanitization within the test_email settings action, where the email parameter is directly processed without adequate security measures. When an SMTP rejection occurs, the recipient address is reflected back in the exception message and subsequently rendered through an inline ERB template, creating a direct code execution vector for attackers who can manipulate this reflection.
The technical implementation of this vulnerability relies on the Rails framework's template rendering capabilities and demonstrates a classic server-side template injection pattern. Attackers can exploit this by submitting a malicious email parameter containing ERB expressions such as <%= system('id') %> or other Ruby code constructs through the admin settings test_email endpoint. The application's failure to properly escape or validate user-supplied input before incorporating it into the ERB template results in the execution of arbitrary Ruby commands with the privileges of the Rails process user, which typically operates with web server permissions.
The operational impact of this vulnerability is severe as it allows authenticated attackers with administrative privileges to achieve full command execution on the affected system. This creates a significant risk for organizations using CamaleonCMS, as successful exploitation can lead to complete system compromise, data exfiltration, and potential lateral movement within network environments. The vulnerability affects the application's configuration management functionality and represents a direct threat to the integrity and confidentiality of the CMS environment. Attackers can leverage this to establish persistent access, escalate privileges, or deploy additional malicious payloads.
Organizations should immediately implement mitigations including input validation and sanitization for all user-supplied parameters within the test_email endpoint, proper escaping of reflected content in error messages, and restricting administrative access to only trusted users. The vulnerability aligns with CWE-94, which describes improper control of generation of code, and maps to ATT&CK technique T1059 for command and scripting interpreter. Additionally, implementing web application firewall rules to detect and block suspicious ERB template expressions and conducting regular security audits of template rendering processes can significantly reduce the risk exposure. The fix should involve proper parameter sanitization and ensuring that reflected content never enters the template evaluation context without appropriate escaping mechanisms.