CVE-2026-8859
CRITICAL 9.9IBM Langflow OSS 1.0.0 through 1.10.0 Langflow could allow an attacker to write arbitrary files to unintended locations due to improper input validation in the APIRequest component. A path traversal vulnerability exists when the "Save to File" feature is enabled, where filenames extracted from HTTP response Content-Disposition headers are not sanitized before being joined to the temporary directory path. An attacker controlling an external HTTP server can supply crafted filename values containing path traversal sequences (e.g., ../), enabling arbitrary file writes to locations accessible by the Langflow process.
Severe if exploited (CVSS 9.9), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.4%chance of exploitation in 30 days · 28th percentile
Impact if exploited
9.9CVSS 3.1 · CRITICAL
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityHigh
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ⚠Privileges: Requires a low-privilege account
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
- github-search Search GitHub for public PoC repos
Test against your own equipment
curl -s https://vulnpedia.com/cve/CVE-2026-8859/poc.jsonMachine-readable PoC index for this CVE (for automation).Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-8859/poc.json
Affected
Vendors Ibm Langflow Apple Linux Microsoft
Products Langflow Oss Langflow Macos Linux Kernel Windows
Weakness (CWE)
- CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Known Affected Software Configurations
| Vendor | Product | Version range |
|---|---|---|
| Langflow | Langflow | ≥ 1.0.0 and < 1.10.1 |
All CVSS metrics
- CRITICAL 9.9 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H - CRITICAL 9.9 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H