CVE-2026-19303 in Langflow OSS
Summary
by MITRE • 09/04/2026
IBM Langflow OSS 1.0.0 through 1.11.2 could allow a remote authenticated attacker to delete arbitrary local files or directories due to improper limitation of a pathname to a restricted directory.
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Analysis
by VulDB Data Team • 09/04/2026
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 file system operations, specifically concerning path traversal and insufficient input validation. As an open-source framework designed for building large language model applications, Langflow provides users with various endpoints to manage resources, including files and directories. The core technical deficiency lies in the improper limitation of pathname resolution relative to a restricted directory context. When processing user-supplied file paths or names, the application fails to adequately sanitize inputs that contain sequence characters such as dot-dot-slash (../) or other platform-specific path traversal sequences. This oversight allows an attacker who has successfully authenticated into the system to manipulate internal file pointers, effectively breaking out of the intended sandboxed directory and accessing arbitrary locations on the underlying operating system's file hierarchy.
From a technical perspective, this flaw is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory, which falls within the broader category of path traversal vulnerabilities. The vulnerability manifests when the application constructs file paths by concatenating user-controlled input with base directory strings without performing rigorous normalization or validation checks. By injecting relative path sequences into these inputs, an authenticated attacker can redirect write operations away from the designated safe zone to arbitrary system locations. This capability is particularly dangerous because it bypasses standard access controls that rely on directory boundaries for security enforcement. The flaw exploits the fundamental assumption that user input will always remain within expected bounds, a premise that fails when path manipulation techniques are employed against poorly validated file handling logic.
The operational impact of this vulnerability extends beyond simple data loss or corruption. An attacker with authenticated access can leverage this weakness to delete critical system files, configuration settings, or other application resources located outside the restricted directory structure. This capability directly compromises the integrity and availability aspects of the CIA triad. In a production environment, such actions could lead to service disruption by removing essential runtime components or logs required for monitoring and debugging. Furthermore, if sensitive data is stored in accessible directories adjacent to the Langflow workspace, an attacker could potentially exfiltrate this information before deletion occurs, although the primary reported risk centers on destructive file system manipulation. The ability to delete arbitrary files also facilitates further attacks by removing security controls such as audit logs or access control configurations, thereby masking subsequent malicious activities and complicating forensic analysis efforts.
This vulnerability aligns with specific tactics within the MITRE ATT&CK framework, particularly those related to Defense Evasion and Impact. It corresponds to techniques involving file deletion for defense evasion purposes, allowing attackers to remove evidence of their presence or disable security mechanisms. Additionally, it relates to resource hijacking or destruction under impact categories, where availability is compromised through deliberate data loss. The requirement for authentication means that this vulnerability cannot be exploited by unauthenticated remote actors, which mitigates the risk profile compared to fully open vulnerabilities but still poses a severe threat in environments where insider threats or credential compromise are plausible scenarios.
Mitigation strategies must address both immediate remediation and long-term architectural improvements. The primary solution is to upgrade IBM Langflow to version 1.12.0 or later, where this path traversal issue has been resolved through enhanced input validation and stricter directory confinement logic. For environments unable to immediately patch, administrators should implement strict network segmentation to limit access to the application interface only from trusted sources with verified identities. Additionally, deploying file integrity monitoring solutions can help detect unauthorized deletions in critical directories, providing early warning indicators of exploitation attempts. Application-level mitigations include enforcing allow-listing for permitted characters in filenames and implementing canonicalization checks that resolve all symbolic links and relative path references before processing them against the restricted base directory. Regular security audits focusing on file I/O operations across all application endpoints are recommended to identify similar patterns of improper pathname limitation elsewhere in the codebase, ensuring comprehensive protection against this class of vulnerabilities.