CVE-2026-26957 in libredesk
Summary
by MITRE • 02/20/2026
Libredesk is a self-hosted customer support desk application. Versions prior to 1.0.2-0.20260215211005-727213631ce6 fail to validate destination URLs for webhooks, allowing an attacker posing as an authenticated "Application Admin" to force the server to make HTTP requests to arbitrary internal destinations. This could compromise the underlying cloud infrastructure or internal corporate network where the service is hosted. This issue has been fixed in version 1.0.2-0.20260215211005-727213631ce6.
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Analysis
by VulDB Data Team • 02/20/2026
The vulnerability CVE-2026-26957 affects Libredesk, a self-hosted customer support desk application that has been identified as susceptible to unauthorized HTTP request forwarding through improperly validated webhook destination URLs. This flaw exists in versions prior to 1.0.2-0.20260215211005-727213631ce6 and represents a critical security oversight that enables authenticated attackers with administrative privileges to manipulate the application's webhook functionality. The issue stems from insufficient input validation mechanisms that fail to properly verify the legitimacy and security of destination URLs specified by administrators when configuring webhook integrations.
The technical flaw manifests as a lack of proper URL validation within the webhook configuration process, allowing an authenticated "Application Admin" to specify arbitrary internal network addresses as webhook endpoints. This vulnerability creates a path for server-side request forgery attacks where the compromised application can be coerced into making HTTP requests to internal services that would normally be protected from external access. The flaw directly aligns with CWE-918, which describes server-side request forgery vulnerabilities, and demonstrates how insufficient validation of user-supplied input can lead to unauthorized network access. Attackers can leverage this weakness to probe internal systems, potentially discovering sensitive services, misconfigurations, or vulnerable endpoints that exist within the same network infrastructure hosting the Libredesk application.
The operational impact of this vulnerability extends beyond simple data exfiltration or service disruption, as it can enable attackers to perform reconnaissance on the underlying cloud infrastructure or internal corporate network. An attacker with administrative access could use this vulnerability to map internal network topology, identify running services, or even attempt to exploit other vulnerabilities in internal systems that are not directly exposed to the internet. This represents a significant risk in environments where the application server shares network space with sensitive internal resources, potentially allowing lateral movement attacks or privilege escalation opportunities. The vulnerability also creates opportunities for attackers to perform denial of service attacks against internal services by forcing the application to make excessive requests to target systems.
The mitigation strategy for this vulnerability requires immediate deployment of version 1.0.2-0.20260215211005-727213631ce6 which implements proper URL validation mechanisms for webhook destinations. Organizations should also consider implementing network segmentation to isolate the application server from critical internal systems, establishing firewall rules that restrict outbound connections from the application server, and monitoring webhook activity for suspicious patterns. From an ATT&CK framework perspective, this vulnerability maps to techniques involving server-side request forgery and reconnaissance, potentially leading to privilege escalation and lateral movement within the compromised environment. Security teams should also conduct comprehensive audits of all webhook configurations across their infrastructure to ensure similar validation gaps do not exist in other applications or services. The fix implemented in the updated version demonstrates proper input sanitization and validation practices that align with secure coding standards and help prevent similar vulnerabilities from manifesting in future releases.