Full Report
Attackers are actively exploiting CVE-2026-5027, a high-severity path traversal vulnerability in the AI development platform Langflow, to write arbitrary files on exposed servers. [...]
Analysis Summary
# Vulnerability: Path Traversal in Langflow File Upload
## CVE Details
- **CVE ID:** CVE-2026-5027
- **CVSS Score:** High Severity (Specific numerical score not provided in article, but categorized as "High")
- **CWE:** CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
## Affected Systems
- **Products:** Langflow (AI development platform) and `langflow-base` Python package.
- **Versions:**
- Langflow versions prior to 1.9.0.
- `langflow-base` versions prior to 0.8.3.
- **Configurations:** Systems where unauthenticated auto-login is enabled (default setting), allowing access to API endpoints without credentials.
## Vulnerability Description
The vulnerability exists within the `POST /api/v2/files` endpoint. The application fails to sanitize the `filename` parameter provided in multipart form data. An attacker can use path traversal sequences (e.g., `../`) to bypass intended directory restrictions and write arbitrary files to any location on the file system accessible by the application process.
## Exploitation
- **Status:** Exploited in the wild; PoC activity observed in honeypots.
- **Complexity:** Low (Single unauthenticated request can obtain a session token).
- **Attack Vector:** Network (Remote).
## Impact
- **Confidentiality:** Categorized as High (Potential to read sensitive configuration files if combined with other flaws).
- **Integrity:** High (Ability to write/overwrite arbitrary files on the server).
- **Availability:** High (Potential to disrupt service by overwriting critical system or application files).
## Remediation
### Patches
- **Langflow Application:** Upgrade to version **1.9.0** or the latest version **1.10.0**.
- **Python Package:** Upgrade `langflow-base` to version **0.8.3** or higher.
### Workarounds
- **Disable Auto-Login:** Disable the unauthenticated auto-login feature to require credentials for API access.
- **Network Restrictions:** Restrict access to the Langflow interface to trusted IP addresses or via a VPN/Internal network only, as approximately 7,000 instances are currently publicly exposed.
## Detection
- **Indicators of Compromise:**
- Presence of unexpected "test" files in system directories.
- HTTP POST requests to `/api/v2/files` containing `../` sequences in the `filename` parameter.
- **Detection Methods:** Monitor web server logs for path traversal patterns and audit the filesystem for unauthorized file creations in the Langflow environment.
## References
- Tenable Research Advisory: hxxps[://]www[.]tenable[.]com/security/research/tra-2026-26
- Snyk Vulnerability DB: hxxps[://]security[.]snyk[.]io/vuln/SNYK-PYTHON-LANGFLOWBASE-15842030
- Langflow GitHub Releases: hxxps[://]github[.]com/langflow-ai/langflow/releases/tag/v1.10.0
- BleepingComputer Article: hxxps[://]www[.]bleepingcomputer[.]com/news/security/path-traversal-flaw-in-ai-dev-platform-langflow-exploited-in-attacks/