CVE-2026-5027 Langflow - Path Traversal Arbitrary File Write via upload_user_file
Attackers can write arbitrary files to the server via unsanitized filename input in the file upload endpoint, potentially leading to code execution.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-5027?
CVE-2026-5027 is a high-severity path traversal vulnerability in Langflow Langflow, published on 27 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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 ('../').
Weakness: CWE-22
Which versions are affected by CVE-2026-5027?
It affects 1 product.
Products include Langflow Langflow.
How do I fix CVE-2026-5027?
No fix has been published for CVE-2026-5027 yet. Limit exposure of the affected software until one is available.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-5027 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-5027 exists.
Public exploit code: 1 Exploit-DB entry, 1 Nuclei template and 8 proofs of concept on GitHub.
Other vulnerabilities in Langflow Langflow
Sources
Also known as GHSA-wr3v-m658-mf42.