CVE-2026-12766 in Langflow OSS
Summary
by MITRE • 09/15/2026
IBM Langflow OSS 1.0.0 through 1.11.2 is vulnerable to server-side request forgery (SSRF). This may allow an authenticated 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 • 09/15/2026
The vulnerability identified in IBM Langflow versions 1.0.0 through 1.11.2 represents a critical server-side request forgery flaw that compromises the integrity of the application by allowing an authenticated attacker to manipulate outbound HTTP requests initiated by the server. This type of vulnerability arises when the software fails to properly validate or sanitize user-supplied input before using it as part of a URL for network communication. In this specific context, Langflow likely accepts URLs or endpoints from users within its workflow definitions and subsequently fetches content from those locations without adequate restrictions on which internal or external resources can be accessed. This lack of validation enables an attacker to craft malicious requests that direct the server to interact with unintended targets, effectively turning the application into a proxy for unauthorized network activity.
From a technical perspective, this flaw aligns closely with CWE-918, Server-Side Request Forgery (SSRF), which describes weaknesses where a web server retrieves data from a user-supplied URL without sufficient validation of the destination address. The operational impact is significant because it allows an authenticated adversary to perform network enumeration against internal services that are not exposed to the public internet but remain accessible within the same virtual private cloud or local network segment. By leveraging this vulnerability, attackers can probe for sensitive backend systems such as database servers, administrative interfaces, or metadata endpoints of cloud infrastructure providers like AWS EC2 instance metadata service. This capability facilitates further exploitation by revealing internal architecture details and potentially leading to data exfiltration if combined with other vulnerabilities that allow reading the response content returned by these internal services.
The security implications extend beyond simple network discovery as described in MITRE ATT&CK technique T1598, which covers Phishing for Information or Gathering Victim Identity Information via SSRF when used to harvest credentials or configuration data from cloud metadata endpoints. Additionally, this vulnerability falls under the broader category of improper input validation and can be mapped to CWE-20 if the root cause involves insufficient sanitization of URL parameters before processing. The presence of authentication as a prerequisite for exploitation indicates that while external unauthenticated actors are not immediately at risk, any compromised user account or insider threat actor with valid credentials poses a severe risk to the organization's internal network security posture.
To mitigate this vulnerability, organizations running affected versions must upgrade IBM Langflow to version 1.12.0 or later where these input validation controls have been implemented. In scenarios where immediate patching is not feasible, administrators should implement strict allowlists for outbound connections at the application level, ensuring that only predefined and trusted domains can be accessed by the server. Network-level mitigations such as firewall rules restricting egress traffic from Langflow servers to known internal IP ranges or blocking access to cloud metadata endpoints like 169.254.169.254 can also reduce the blast radius of this exploit. Continuous monitoring of outbound network logs for anomalous connection attempts originating from the application server is recommended to detect potential exploitation activities in real time and ensure that no unauthorized internal resources are being accessed through forged requests.