CVE-2026-7528: Unauthenticated File Upload Vulnerability Allows Disk Space Exhaustion and Path Disclosure in Langflow OSS

Synopsis

An uncontrolled resource consumption vulnerability in IBM Langflow OSS (versions 1.0.0 through 1.9.0) allows an authenticated remote attacker to exhaust disk space by uploading files without adequate size or rate limits, and may expose internal file-system paths in the process. The attacker must reach the service over the network and hold a low-privilege account, but no victim interaction is needed. Successful exploitation disrupts the Langflow service by filling available disk space, potentially taking the instance offline, and leaks partial path information. HarborGuard is tracking this advisory and will make a patched-image rebuild available as soon as an upstream fix is published.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

  The attacker must reach the Langflow service over the network; the CVSS vector specifies AV:N, meaning no local access or physical proximity is required.

• AuthenticationRequired

  A valid low-privilege account is sufficient; the CVSS vector specifies PR:L, so anonymous access alone is not enough to trigger the upload endpoint.

• Victim interactionNot required

  No user action is needed on the target side; the attacker drives the entire exploit without any social-engineering step.

• Attack complexityDetail

  Attack complexity is low (AC:L), meaning the exploit is reliable and requires no race conditions, special memory layout, or other variable environmental conditions.

Blast Radius

• Fills available disk space on the host running Langflow, causing the service to stop accepting new data or crash outright.
• Disrupts any co-located services or sidecar containers that share the same underlying storage volume.
• Exposes internal file-system path strings that can inform follow-on attacks targeting directory traversal or local file inclusion weaknesses.
• Confidentiality impact is partial (C:L): path disclosure is limited but provides an attacker with structural knowledge of the deployment.