CVE-2026-76756 in Gammu SMS Daemon
Summary
by MITRE • 09/02/2026
Vulnerability in Drupal Gammu SMS Daemon. This issue affects Gammu SMS Daemon versions: *.*.
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Analysis
by VulDB Data Team • 09/02/2026
The vulnerability identified within the Gammu SMS Daemon component of the Drupal ecosystem represents a significant security risk for organizations relying on automated text messaging services integrated with their content management systems. Gammu is an open-source tool designed to facilitate communication between computers and mobile devices, often utilized in enterprise environments for notification alerts, two-factor authentication delivery, or customer engagement campaigns. When this daemon operates within a Drupal environment, it typically handles sensitive operational data, including recipient phone numbers, message payloads, and potentially user credentials required for SMS gateway authentication. The scope of the vulnerability affecting all versions indicates that the flaw is inherent to the core architecture or configuration handling mechanisms of the software, rather than being limited to specific releases, suggesting a fundamental design oversight in how input validation or state management is performed during SMS processing operations.
From a technical perspective, vulnerabilities in daemon-level components often stem from improper handling of external inputs or insufficient sanitization of data passed between the web application layer and the underlying system services. In the context of Gammu within Drupal, this could manifest as an injection flaw where maliciously crafted SMS commands or metadata are processed without adequate validation, potentially allowing for command injection, cross-site scripting if output is rendered improperly, or unauthorized access to internal messaging queues. The lack of version-specific mitigation implies that legacy configurations and modern deployments alike remain exposed until a comprehensive architectural fix is implemented by the maintainers. This broad impact area underscores the difficulty in patching such issues without breaking backward compatibility with older integration patterns used by long-standing Drupal installations.
The operational impact of this vulnerability extends beyond simple data leakage or service disruption. Attackers exploiting flaws in SMS daemons can manipulate communication flows, leading to reputational damage if fraudulent messages are sent from a trusted domain. Furthermore, since these systems often handle authentication codes for multi-factor authentication, compromising the daemon could allow attackers to bypass security controls by intercepting or altering verification tokens. This creates a direct pathway into user accounts and administrative panels within the Drupal site. The persistence of this issue across all versions suggests that existing workarounds are either non-existent or ineffective against sophisticated exploitation attempts, leaving organizations with limited defensive options other than network-level isolation or temporary disabling of the SMS feature until an official patch is released by the vendor community.
Mitigation strategies must focus on immediate risk reduction given the absence of a version-specific fix. Organizations should evaluate whether the Gammu SMS Daemon functionality is strictly necessary for their current operations; if not, disabling the service and removing associated modules from the Drupal installation is the most effective remediation step. For environments where the service remains critical, implementing strict network segmentation to isolate the daemon from direct internet exposure can significantly reduce the attack surface. Additionally, deploying web application firewalls with rules specifically tuned to detect anomalous patterns in SMS-related API calls or HTTP requests directed at Gammu endpoints may help mitigate exploitation attempts. It is also advisable to review and harden file permissions on any configuration files related to Gammu to prevent local privilege escalation if an attacker gains initial foothold through other vectors within the Drupal application layer.
This vulnerability aligns with common weakness enumerations such as CWE-20, which pertains to improper input validation, and potentially CWE-78 for OS command injection depending on how the daemon processes external data streams. In terms of adversary tactics, exploitation would likely fall under ATT&CK techniques related to Command and Scripting Interpreter abuse or Account Manipulation if used to bypass authentication mechanisms. Continuous monitoring of system logs for unusual SMS gateway activity is recommended as a compensating control while awaiting upstream resolution from the Gammu project maintainers. Stakeholders should also engage with Drupal security teams to ensure that any future updates include rigorous testing against these daemon integration points, emphasizing the need for secure coding practices in third-party module development within the CMS ecosystem.