CVE-2026-19305 in Langflow OSS
Summary
by MITRE • 09/04/2026
IBM Langflow OSS 1.0.0 through 1.11.2 could allow a remote attacker to obtain sensitive information due to server-side request forgery.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 09/05/2026
The vulnerability identified in IBM Langflow versions 1.0.0 through 1.11.2 represents a critical security flaw rooted in the application's handling of external network requests, specifically manifesting as Server-Side Request Forgery or SSRF. This class of vulnerabilities occurs when an application accepts a URL or endpoint from user input and subsequently makes a request to that location without sufficiently validating or sanitizing the destination. In the context of Langflow, which is designed for building and deploying large language model applications, this flaw allows a remote attacker to craft malicious inputs that trick the server into initiating connections to internal resources that are otherwise inaccessible from the public internet. The core technical failure lies in the lack of rigorous input validation on parameters that dictate outbound network traffic, enabling an adversary to manipulate the target address to point toward localhost interfaces, cloud metadata services, or private subnet endpoints.
From a technical perspective, SSRF vulnerabilities exploit the trust relationship between the application server and its internal infrastructure. When Langflow processes user-supplied data for operations such as fetching external documents, integrating with third-party APIs, or loading resources within a workflow chain, it fails to enforce strict allowlists on destination hosts or protocols. This oversight permits attackers to bypass firewalls that typically restrict direct access from the internet to internal systems by routing requests through the vulnerable application itself. The attacker can specify URLs using various schemes such as HTTP, HTTPS, FTP, and potentially file:// or gopher:// depending on the underlying library implementation. By directing these requests toward sensitive endpoints, the server inadvertently acts as a proxy, exposing data that should remain confidential to the external threat actor.
The operational impact of this vulnerability is severe, primarily centering on unauthorized information disclosure. An attacker leveraging this SSRF flaw can access internal services running on the same host or within the private network where Langflow is deployed. This includes but is not limited to database management systems, administrative consoles, cloud instance metadata endpoints such as AWS EC2 Instance Metadata Service version 1 which often contain temporary credentials and security tokens, and other microservices that are not exposed publicly. The exfiltration of these sensitive details can lead to a complete compromise of the underlying infrastructure. If an attacker retrieves API keys or authentication tokens from cloud metadata services, they may gain persistent access to cloud resources, leading to data breaches, service disruption, or further lateral movement within the network environment.
This vulnerability aligns with Common Weakness Enumeration identifier CWE-918 which specifically addresses Server-Side Request Forgery attacks where a web server makes requests based on user input without proper validation. Furthermore, in terms of tactical mapping according to MITRE ATT&CK framework, this behavior corresponds to techniques involving Taint Analysis failures and potentially Data from Cloud Infrastructure under the collection phase if metadata services are targeted. The exploitation chain typically involves crafting specific HTTP requests with manipulated parameters that force the server to connect to internal destinations, thereby bypassing network-level security controls designed to isolate external-facing applications from backend systems.
Mitigation strategies for this vulnerability require both immediate patching and architectural adjustments. Users running IBM Langflow versions 1.0.0 through 1.11.2 should immediately upgrade to the latest patched version where input validation mechanisms have been strengthened to prevent SSRF exploitation. Beyond software updates, organizations must implement network-level controls such as egress filtering to restrict outbound connections from application servers to only known and necessary destinations. Additionally, deploying a reverse proxy or web application firewall with specific rules to detect and block requests containing internal IP addresses or cloud metadata endpoints can provide an additional layer of defense. It is also critical to ensure that any external-facing services do not have direct access to sensitive internal resources by utilizing proper network segmentation and zero-trust principles to limit the blast radius in case of future vulnerabilities.