CVE-2026-51583 in Memos
Summary
by MITRE • 08/11/2026
An issue in usememos through v0.30.0 allows a remote authenticated attacker to perform Server-Side Request Forgery (SSRF) via the Webhook validation mechanism in internal/webhook/validate.go, by setting a webhook target to an internal address.
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Analysis
by VulDB Data Team • 08/11/2026
The vulnerability identified in usememos versions up to v0.30.0 represents a critical server-side request forgery flaw that undermines the application's security posture through its webhook validation mechanism. This issue stems from insufficient input validation within the internal/webhook/validate.go component, where the system fails to properly sanitize or restrict webhook target URLs that could potentially point to internal network resources. The vulnerability specifically affects authenticated users who can craft malicious webhook configurations, creating a pathway for attackers to probe internal systems and potentially exfiltrate sensitive information or escalate privileges.
The technical exploitation of this flaw occurs when an authenticated attacker manipulates the webhook validation process by specifying internal network addresses as webhook targets. This allows the application to make HTTP requests to internal services that would normally be protected from external access, effectively bypassing network segmentation controls. The vulnerability operates at the application layer and leverages the legitimate webhook functionality to perform unauthorized network communications, making it particularly challenging to detect through traditional network monitoring approaches. The flaw demonstrates a classic SSRF pattern where the application acts as an intermediary for attacker-controlled requests without proper validation of destination addresses.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with potential access to internal services that may contain sensitive data or administrative interfaces. An attacker could leverage this weakness to enumerate internal network resources, probe for vulnerable services, or even attempt to exploit other systems within the internal network that are not directly exposed to external traffic. This capability significantly increases the attack surface and could enable further compromise of the system through lateral movement or privilege escalation attempts. The vulnerability is particularly concerning in environments where usememos serves as a central collaboration platform, as it could provide unauthorized access to internal resources that are typically protected by network security controls.
Mitigation strategies for this vulnerability should focus on implementing strict input validation and address whitelisting for webhook targets within the internal/webhook/validate.go component. Organizations should enforce network segmentation policies that prevent outbound connections from the usememos application to internal addresses, while also implementing proper URL sanitization routines that reject or normalize suspicious address formats. The fix should align with established security practices such as those outlined in CWE-918 for server-side request forgery and should be consistent with ATT&CK techniques targeting SSRF vulnerabilities. Additionally, organizations should consider implementing network-level controls to restrict outbound traffic from the application server and establish monitoring procedures to detect anomalous webhook behavior that could indicate exploitation attempts.