IBM Langflow Desktop EUVD-2026-26434

Authentication is required - attackers must possess valid credentials for an IBM Langflow Desktop instance or compromise an authorized user account. The vulnerability is triggered when the attacker crafts a specially formatted URL or request parameter containing directory traversal sequences (/../ or similar) targeting a file write or path construction endpoint in the application. The vulnerability is not limited to specific deployment configurations or non-default settings; it affects all vulnerable versions (1.2.0-1.8.4) under default operation. Exploitation is limited by the file system permissions of the process running Langflow Desktop - the attacker cannot write to directories outside the process's write scope, and on hardened systems with SELinux or AppArmor, exploitation impact may be further constrained.

The CVSS 6.5 score reflects a network-accessible vulnerability requiring authentication (AV:N, PR:L) with low attack complexity (AC:L) and high integrity impact (I:H). The authentication requirement significantly reduces real-world risk compared to an unauthenticated variant, as attackers must first gain valid credentials or compromise an authorized user account. However, the integrity impact is severe - arbitrary file writes can overwrite application binaries, configuration files, or system files depending on process privileges. The lack of a public exploit identifier (KEV status unknown from provided data) suggests either limited active exploitation or that exploitation has not yet been formally documented by CISA. Organizations must weigh the authentication barrier against the severity of post-exploitation impact. The vulnerability is not in a cryptographic or authentication mechanism itself, reducing likelihood of supply-chain or mass-exploitation scenarios. Risk is highest in environments where Langflow Desktop is deployed with elevated privileges or where multiple users share authenticated access.

An authenticated user with valid credentials to Langflow Desktop crafts a malicious HTTP request with a URL parameter containing path traversal sequences, such as GET /api/files?path=../../../../etc/passwd. The application fails to validate or canonicalize this input and constructs a file write operation that escapes the intended application directory, overwriting a critical configuration file or injecting code into a startup script. Upon next application restart or process reload, the attacker-modified file executes with the privileges of the Langflow Desktop process.