What’s Vulnerable › Vulnerabilities
CVE-2026-5027: Langflow - Path Traversal Arbitrary File Write via upload_user_file
- Severity: high (CVSS 8.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 40.0% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2026-03-27 · updated 2026-08-18
- Weakness: CWE-22
Description
The 'POST /api/v2/files' endpoint does not sanitize the 'filename' parameter from the multipart form data, allowing an attacker to write files to arbitrary locations on the filesystem using path traversal sequences ('../').
Affected products
- IBM Langflow OSS: before 1.9.0 — fixed in 1.9.0
How to fix
Upgrade to a fixed version: IBM Langflow OSS 1.9.0. Check the vendor advisory for mitigations.
References
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