Vulnerability · Published Mar 27, 2026 · Assigned by GitHub_M
CVE-2026-34046Langflow: Authenticated Users Can Read, Modify, and Delete Any Flow via Missing Ownership Check
High 8.7
In plain English
A high-severity authorization bypass via user-controlled key in langflow from langflow-ai. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 41% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to version 1.5.1, the `_read_flow` helper in `src/backend/base/langflow/api/v1/flows.py` branched on the `AUTO_LOGIN` setting to decide whether to filter by `user_id`. When `AUTO_LOGIN` was `False` (i.e., authentication was enabled), neither branch enforced an ownership check — the query returned any flow matching the given UUID regardless of who owned it. This allowed any authenticated user to read any other user's flow, including embedded plaintext API keys; modify the logic of another user's AI agents, and/or delete flows belonging to other users. The vulnerability was introduced by the conditional logic that was meant to accommodate public/example flows (those with `user_id = NULL`) under auto-login mode, but inadvertently left the authenticated path without an ownership filter. The fix in version 1.5.1 removes the `AUTO_LOGIN` conditional entirely and unconditionally scopes the query to the requesting user.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | langflow | 1.5.1 | GHSA-8c4j-f57c-35cf |
| PyPI | langflow | 1.5.1 | PYSEC-2026-2567 |
| PyPI | langflow-base | 0.5.1 | GHSA-8c4j-f57c-35cf |
| PyPI | langflow-base | 0.5.1 | PYSEC-2026-2570 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| langflow-ai | langflow | < 1.5.1 |
| langflow-ai | langflow-base | < 0.5.1 |
Weakness: CWE-639, CWE-862 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
References
- https://github.com/langflow-ai/langflow/security/advisories/GHSA-8c4j-f57c-35cf x_refsource_CONFIRM
- https://github.com/langflow-ai/langflow/pull/8956 x_refsource_MISC