CVE-2026-102590 in Langflow OSS
Summary
by MITRE • 10/29/2026
IBM Langflow OSS 1.0.0 through 1.12.3 could allow a remote authenticated attacker to obtain sensitive information due to a server-side request forgery vulnerability.
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Analysis
by VulDB Data Team • 10/29/2026
The identified security flaw within IBM Langflow versions ranging from 1.0.0 to 1.12.3 constitutes a critical Server-Side Request Forgery, commonly referred to as SSRF. This vulnerability arises when the application fails to adequately validate or sanitize user-supplied input that is subsequently used by the server to construct and execute HTTP requests. In this specific context, an attacker who has successfully authenticated to the Langflow interface can manipulate these inputs to direct the backend server into making connections to internal resources or external systems under the control of the adversary. The core technical deficiency lies in the lack of rigorous input validation mechanisms that would typically restrict the protocol, host, and port allowed for outbound requests initiated by the application logic.
From a technical perspective, SSRF vulnerabilities exploit the trust relationship between an application server and its internal network infrastructure or external services. When Langflow processes user-provided URLs or endpoints without proper filtering, it effectively acts as a proxy on behalf of the attacker. This capability allows the remote authenticated actor to bypass firewalls that might otherwise restrict direct access from their IP address to sensitive internal assets such as cloud metadata services, internal databases, administrative interfaces, or other microservices within the same network segment. The vulnerability is particularly dangerous because it leverages existing authentication credentials, thereby blending malicious activity with legitimate user behavior and making detection through standard perimeter security controls more difficult.
The operational impact of this vulnerability centers on unauthorized information disclosure and potential further compromise of the underlying infrastructure. By leveraging SSRF, an attacker can probe internal network services that are not exposed to the public internet, potentially extracting sensitive configuration data, authentication tokens, or proprietary application logic stored in accessible endpoints. In cloud environments, such as those where Langflow might be deployed, this often leads to the retrieval of instance metadata and credentials from cloud provider APIs, which can then be used to escalate privileges and gain full control over compute instances. The ability to interact with internal services also opens avenues for denial-of-service attacks against critical backend components by flooding them with requests initiated through the vulnerable application.
This vulnerability aligns closely with CWE-918, which defines Server-Side Request Forgery as a weakness where an attacker causes the server-side application to make requests to unintended destinations. Furthermore, in terms of offensive security frameworks, this exploit maps directly to MITRE ATT&CK technique T1571, specifically Subversion Trusting Executable and Dynamic Link Libraries if file inclusion is involved, or more broadly to network reconnaissance techniques that utilize trusted applications as proxies for lateral movement. The authenticated nature of the attack means it falls under initial access vectors where valid credentials are abused rather than stolen through brute force or phishing, highlighting a risk associated with privilege escalation within the application layer itself.
To mitigate this vulnerability, organizations must immediately apply vendor-provided patches to update Langflow to version 1.12.4 or later, which addresses these input validation deficiencies. In environments where patching is not immediately feasible, network-level controls should be implemented to restrict outbound traffic from servers running the vulnerable application. This includes configuring firewalls and proxy rules to whitelist only known, necessary external domains and blocking access to private IP address ranges such as 10.x.x.x, 172.16.x.x through 172.31.x.x, and 192.168.x.x. Additionally, implementing strict input validation on the application side is essential; developers should enforce allowlists for permitted protocols like HTTP or HTTPS only, reject requests containing IP addresses in favor of domain names that are resolved securely, and disable redirects to prevent attackers from bypassing initial filters through redirection chains. Regular security audits and penetration testing focused on SSRF scenarios will help identify similar weaknesses in other components of the application stack.