langflow has Unauthenticated IDOR on Image Downloads

Description

Summary

The /api/v1/files/images/{flow_id}/{file_name} endpoint serves image files without any authentication or ownership check. Any unauthenticated request with a known flow_id and file_name returns the image with HTTP 200.

Details

src/backend/base/langflow/api/v1/files.py:138-164download_image takes flow_id: UUID as a bare path parameter with no Depends(get_flow) or CurrentActiveUser. All other file routes (download_file, upload_file, list_files, delete_file) use Depends(get_flow) which enforces both authentication and ownership. There is no global auth middleware on /api/v1; protection is per-endpoint only.

PoC

curl -v "http://localhost:7860/api/v1/files/images/<flow_uuid>/<filename.png>"
# Returns HTTP 200 with image bytes, no auth header required

Impact

Unauthenticated cross-tenant data leak. In a multi-tenant deployment, any attacker who can discover or guess a flow_id (UUIDs can be leaked through other API responses) can download any user's uploaded images without credentials.

Basic information

Type
reviewed
Severity
high
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2026-03-20 20:47:10 UTC
Updated
2026-06-06 00:56:14 UTC
GitHub reviewed
2026-03-20 20:47:10 UTC
NVD published
2026-03-24

EPSS Score

Score Percentile
0.05% 15.95%

CVSS Scores

Base score Version Severity Vector
7.5 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.

Identifiers

CWEs

CWE id Name
CWE-284 Improper Access Control
CWE-639 Authorization Bypass Through User-Controlled Key
CWE-862 Missing Authorization

Credits

  • akshatgit (reporter)
  • abhinavagarwal07 (remediation_reviewer)
  • andifilhohub (remediation_developer)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
pip langflow >= 1.0.0, < 1.9.0 1.9.0

References

cvelogic Threat Intelligence