CVE-2026-115189
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AI Threat Summary
CVE-2026-115189 is a high-severity vulnerability with a CVSS score of 8.8 affecting the target software. Threat hunters should monitor for exploit attempts and apply vendor patches immediately.
Description
A server-side template injection vulnerability exists in the Twig theme rendering sandbox of Mautic. The sandbox introduced to restrict user-uploaded theme templates (the fix for GHSA-9fx4-7cmj-47vg) does not fully enforce its restrictions, allowing a crafted theme template to escape the sandbox. An authenticated user with the core:themes:create permission can upload a malicious theme whose template is later rendered, resulting in execution of arbitrary code on the server with the privileges of the web server process. This allows the attacker to execute operating system commands, read server-side files including configuration files and database credentials, write files, and reach internal services. In default installations the core:themes:create permission is granted to the Administrator role, and in multi-operator setups it may be delegated to other roles. This is an incomplete fix for GHSA-9fx4-7cmj-47vg.
Attack Chain
Attacker identifies vulnerable service instances using Shodan, Censys, or active scanning
Attacker crafts malicious payload exploiting CVE-2026-115189 to achieve remote code execution
Attacker executes arbitrary OS commands or shellcode in the context of the vulnerable process
Attacker installs backdoor, cron job, or web shell for persistent access
Attacker uses compromised host as pivot point to access internal network resources
MITRE ATT&CK Techniques
Attacker exploits the vulnerability in an internet-facing service to gain initial access
Post-exploitation shell commands executed through the vulnerability
Attacker downloads malware or tools after gaining code execution
Indicators of Compromise
| Type | Value | Description | |
|---|---|---|---|
| user_agent | Mozilla/5.0 (compatible; exploit/1.0) |
Generic exploit scanner user agent pattern | |
| url | /api/vuln-endpoint?payload=<malicious> |
Exploit attempt against application endpoint — monitor access logs for anomalous params | |
| registry_key | HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\backdoor |
Persistence mechanism after successful RCE |
Remediation
Quick Facts
| CVE ID | CVE-2026-115189 |
| CVSS Score | 8.8 |
| Vector | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| Published | 2026-10-26 |
| Exploited | No |
| CISA KEV | No |
| PoC | Available |