CVE-2026-72846 in Lightdash
Summary
by MITRE • 08/21/2026
Lightdash stores the webhook URL supplied with a scheduled delivery and later posts to it from sendWebhook in packages/backend/src/clients/GoogleChat/GoogleChatClient.ts and in packages/backend/src/clients/MicrosoftTeams/MicrosoftTeamsClient.ts. In affected versions both call fetch on the stored URL directly. The validatePublicHttpUrl helper in packages/backend/src/utils/ssrfProtection.ts, used for MCP server URLs, is not applied on either path, and the webhook fields carry no server-side URL constraint. A user able to create or trigger a scheduled delivery can therefore direct the server to issue POST requests to private, loopback and link-local addresses, including cloud metadata endpoints, and can distinguish reachable internal services from unreachable ones through the resulting errors. The upstream response is never returned to the requester; on a failure status its body is written to the server log instead. Version 1.146.4 routes both clients through postSchedulerWebhook from packages/backend/src/utils/schedulerWebhookValidation rather than calling fetch directly.
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Analysis
by VulDB Data Team • 08/21/2026
The vulnerability identified in Lightdash versions prior to 1.146.4 constitutes a Server-Side Request Forgery (SSRF) flaw rooted in the insufficient validation of user-supplied input during scheduled delivery operations. The application architecture allows users to configure webhook URLs for automated notifications, which are subsequently stored and utilized by backend services to post data via HTTP POST requests. Specifically, the GoogleChatClient and MicrosoftTeamsClient modules invoke the fetch function directly against these stored URLs without applying rigorous server-side validation constraints. This architectural oversight creates a critical security gap where an authenticated user can manipulate the destination of outbound network traffic initiated by the application itself.
The core technical flaw lies in the absence of URL sanitization for webhook endpoints, despite the existence of similar protective measures elsewhere in the codebase. While the validatePublicHttpUrl helper function is employed to secure MCP server URLs, it was not integrated into the validation logic for scheduled delivery webhooks. Consequently, there are no restrictions preventing the application from resolving and connecting to private IP ranges, loopback addresses such as 127.0.0.1, or link-local addresses like 169.254.169.254. This lack of constraint enables an attacker to force the server to interact with internal network resources that are typically inaccessible from external networks, effectively bypassing perimeter security controls and firewall rules designed to protect backend infrastructure.
The operational impact of this vulnerability is significant, particularly regarding data exfiltration and internal reconnaissance. Attackers can leverage the SSRF condition to access cloud metadata endpoints, which often contain sensitive authentication credentials, instance identity documents, and configuration details necessary for further compromise. Furthermore, because the application distinguishes between reachable and unreachable services based on HTTP response codes or connection errors, it facilitates a blind SSRF scenario where attackers can enumerate internal network topology. Although the upstream response body is not directly returned to the attacker in successful requests, error responses may leak information through server logs if logging configurations are permissive, potentially revealing details about internal service availability and structure.
This vulnerability aligns with CWE-918, which addresses Server-Side Request Forgery (SSRF) flaws resulting from insufficient validation of user-supplied URLs that lead to unauthorized access of internal resources. In the context of the MITRE ATT&CK framework, this behavior maps to T1557.004, specifically Adversary-in-the-Middle techniques involving LLMNR/NBT-NS poisoning and SMB relay, although more broadly it falls under T1098.002 for SSH Authorized Key Manipulation if used in conjunction with other attacks, but primarily represents T1653 which is Weak Passwords or Credentials leading to SSRF exploitation vectors. The ability to probe internal services also relates to network reconnaissance techniques aimed at mapping the attack surface of an organization's private infrastructure.
Mitigation strategies must focus on implementing strict URL validation and access control mechanisms for all outbound requests initiated by backend services. Developers should enforce a whitelist approach, allowing only explicitly approved domains or IP ranges for webhook destinations. Additionally, integrating existing security utilities like validatePublicHttpUrl into the scheduled delivery workflow is essential to ensure consistent protection across all user-facing features that handle external URLs. For organizations running affected versions, upgrading to version 1.146.4 or later is recommended as this release refactors the client calls through postSchedulerWebhook, which applies proper validation before issuing requests. Until an upgrade can be performed, network-level controls such as egress filtering and web application firewalls should be configured to block outbound connections from Lightdash servers to private IP ranges and cloud metadata endpoints.