CVE-2026-12767 in Langflow OSS
Summary
by MITRE • 09/14/2026
IBM Langflow OSS 1.0.0 through 1.11.5 is vulnerable to server-side request forgery (SSRF). This may allow an unauthenticated attacker to send unauthorized requests from the system, potentially leading to network enumeration or facilitating other attacks.
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Analysis
by VulDB Data Team • 09/14/2026
The vulnerability identified in IBM Langflow versions 1.0.0 through 1.11.5 represents a critical server-side request forgery flaw that stems from insufficient validation of user-supplied input when constructing outbound HTTP requests. In this architecture, the application acts as an intermediary for network operations, allowing users to specify target URLs or endpoints which are then fetched by the backend service. The core technical deficiency lies in the lack of rigorous allow-listing or strict sanitization mechanisms applied to these URL parameters before they are processed by the underlying request library. This oversight enables an unauthenticated actor to manipulate the destination address, directing the server to communicate with internal network resources that should remain inaccessible from external contexts. By exploiting this misconfiguration, attackers can bypass perimeter security controls such as firewalls and access control lists that typically restrict direct client-to-internal-service communication, effectively using the vulnerable application as a proxy for malicious reconnaissance or data exfiltration activities.
From an operational perspective, the impact of this SSRF vulnerability extends beyond simple unauthorized access to internal services. It facilitates comprehensive network enumeration by allowing attackers to probe internal IP ranges and identify live hosts within the organization's infrastructure. This capability can serve as a stepping stone for more severe attacks, including accessing sensitive metadata endpoints on cloud providers like AWS or Azure, reading local configuration files via file:// protocols if supported by the request library, or interacting with other vulnerable services running on localhost such as database management interfaces or administrative dashboards that lack their own authentication mechanisms. The ability to send unauthorized requests from the system means that an attacker can leverage the server's identity and network privileges, potentially leading to data theft, service disruption, or further compromise of adjacent systems within the trusted zone.
This vulnerability aligns with CWE-918, which defines Server-Side Request Forgery as a flaw where a web application fetches a remote resource without validating the user-supplied URL. Furthermore, it maps directly to MITRE ATT&CK technique T1557, specifically Adversary-in-the-Middle or Lateral Tool Transfer variants that utilize SSRF for network reconnaissance and pivoting. The absence of authentication requirements exacerbates the risk profile significantly, as any external actor with internet access can initiate these malicious requests without needing valid credentials. To mitigate this issue, organizations must immediately upgrade to patched versions released by IBM Langflow after 1.11.5 that address the input validation logic. In environments where upgrading is not immediately feasible, implementing a reverse proxy or web application firewall rule set that blocks outbound connections from the application server to private IP ranges and cloud metadata endpoints can provide effective compensating controls. Additionally, developers should enforce strict allow-listing of permitted domains for all outbound requests and implement robust input sanitization procedures to ensure that only expected and safe URLs are processed by the system.