External risk intelligence
Gotenberg API could allow external attackers to access internal network services.
The Gotenberg PDF API could allow external attackers to bypass security filters and force the server to interact with private internal services. This may expose sensitive files, operational systems, or network controls that were intended to remain isolated. There is no evidence of active exploitation.
Halo Surface Signal
3/ 5Gotenberg is a containerized API used for PDF conversion. It operates as a network-accessible service; however, it is typically deployed as a backend microservice to support other applications, rather than as an edge-facing gateway or public-facing endpoint. While direct exposure is possible, it is not the standard or primary deployment pattern for this type of utility service.
Exposure facts
H – Horizon Alert
A security vulnerability exists within the Gotenberg PDF API that may allow external users to bypass established access restrictions. Due to a flaw in how the system filters web addresses, unauthorized parties could potentially force the application to communicate with private internal services that are intended to be protected from external requests. This is a significant concern because it allows an external actor to cross established security boundaries and interact with restricted network targets.
A – Asset Exposure
This vulnerability affects Gotenberg, a PDF processing API, specifically impacting its features used for webhooks and downloading files. By bypassing intended security restrictions, an external attacker can force the server to interact with internal or loopback network services. Consequently, this could inadvertently expose operational systems, sensitive files, or network controls that were previously isolated from public access. These impacted resources may become accessible to unauthorized parties despite existing security boundaries.
L – Live Threat
We are reviewing a security issue affecting Gotenberg's filtering controls, which could potentially allow unauthorized requests to reach internal network services. At this time, the available context does not indicate active exploitation or observed targeting in the wild. We are continuing to monitor the situation for any new reports regarding public exploit activity.
O – Operational Fix
To address this security concern, please prioritize updating your Gotenberg deployments to the latest version provided by the vendor. This update resolves a flaw in the system's deny-list filtering mechanism that previously allowed for unauthorized outbound requests. Following this update, we recommend having your technical team validate existing configurations to ensure all internal services remain properly restricted and isolated.