CVE-2025-59527 is a Server-Side Request Forgery (SSRF) vulnerability identified in FlowiseAI's Flowise product, specifically in version 3.0.5. Flowise is a drag-and-drop interface designed to build customized large language model workflows. The vulnerability resides in the /api/v1/fetch-links endpoint, which improperly validates user-supplied URLs or links. This flaw allows an unauthenticated attacker to coerce the Flowise server into making arbitrary HTTP requests on their behalf. As a result, the attacker can use the server as a proxy to access internal network resources that are otherwise inaccessible externally. This can lead to reconnaissance of internal web services and their link structures, potentially exposing sensitive internal endpoints or configurations. The vulnerability has a CVSS v3.1 base score of 7.5 (high severity) with the vector AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N, indicating that it is remotely exploitable without authentication or user interaction, and primarily impacts confidentiality by exposing internal network information. The vulnerability does not impact integrity or availability directly. The issue was patched in Flowise version 3.0.6, and no known exploits have been reported in the wild as of the publication date (September 22, 2025).

For European organizations using Flowise 3.0.5, this SSRF vulnerability poses a significant risk to internal network confidentiality. Attackers can leverage the Flowise server to bypass perimeter defenses and access internal web services, potentially exposing sensitive data, internal APIs, or administrative interfaces that are not intended for external access. This could facilitate further lateral movement or targeted attacks within the network. Organizations in sectors with high regulatory requirements for data protection, such as finance, healthcare, and critical infrastructure, may face compliance risks if internal data is exposed. Additionally, the ability to map internal link structures can aid attackers in planning more sophisticated attacks. Since the vulnerability does not require authentication or user interaction, it can be exploited remotely and at scale if the vulnerable version is internet-facing. However, the absence of known exploits in the wild suggests limited active exploitation currently, but the risk remains high if unpatched.

European organizations should immediately upgrade Flowise installations from version 3.0.5 to version 3.0.6 or later, where the SSRF vulnerability has been patched. In addition to patching, organizations should implement network segmentation and firewall rules to restrict outbound HTTP requests from application servers to only necessary destinations, reducing the risk of SSRF exploitation. Employing Web Application Firewalls (WAFs) with rules to detect and block SSRF patterns targeting internal IP ranges can provide additional protection. Monitoring and logging outbound requests from Flowise servers can help detect anomalous activity indicative of SSRF exploitation attempts. Organizations should also review and restrict access to the /api/v1/fetch-links endpoint, applying authentication or IP whitelisting where feasible. Regular vulnerability scanning and penetration testing focused on SSRF and related issues should be incorporated into security programs to identify similar risks proactively.