### Summary Unauthenticated users can upload any amount of data to the server without any limitations. No need for any prior knowledge, only network access to Langflow. This can lead to space exhaustion on the server. In adition, in the response, the absolute path of the uploaded file is reported to the attacker, which is an information leak that can assist in chaining other primitives. Tested on commit 2d67402b1dbaefcbce85a244d4a6cd5e4bda1cfe ### Details Code is in `langflow/api/v1/[endpoints.py](http://endpoints.py/)`: ```python @router.post( "/upload/{flow_id}", status_code=HTTPStatus.CREATED, deprecated=True, ) async def create_upload_file( file: UploadFile, flow_id: UUID, ) -> UploadFileResponse: ... ``` As can be seen above, there is no authentication. There is not validation over `flow_id` as well, unlike other endpoints: ``` flow_id_str = str(flow_id) file_path = await asyncio.to_thread(save_uploaded_file, file, folder_name=flow_id_str) ``` Function `save_uploaded_file` saves the file to local file-system. Suggested fix: 1. Add authentication to route. 2. Only return relative path or filename. ### PoC PoC: ```bash curl 'http://localhost:7860/api/v1/upload/<any_uuid>' -F "file=@<any_file>" ``` Example: ```bash # curl 'http://localhost:7860/api/v1/upload/11111111-1111-1111-1111-111111111111' -F "file=@/tmp/dummy.txt" {"flowId":"11111111-1111-1111-1111-111111111111","file_path":"/Users/ori/Library/Caches/langflow/11111111-1111-1111-1111-111111111111/9d63c3b5b7623d1fa3dc7fd1547313b9546c6d0fbbb6773a420613b7a17995c8.txt"} ``` ### Impact 1. Space exhaustion on server that can lead to Denial-of-Service. 2. Information leak - leakage of absolute path of langflow's cache directory in server. ### Patches Fixed in **1.9.1** via PR [#12831](https://github.com/langflow-ai/langflow/pull/12831). The deprecated `POST /api/v1/upload/{flow_id}` endpoint now uses the `get_flow` dependency, requiring an authenticated user and flow ownership (returns `404` for missing or cross-user flows), and enforces the `max_file_size_upload` limit (`HTTP 413`) — closing the unauthenticated upload and disk-exhaustion vectors. Upgrade to **1.9.1 or later**. Note: the response still returns the file's absolute path (`file_path`); after this fix it is only disclosed to the authenticated owner of the flow. Ori Lahav Security Researcher @ Rubrik Inc.
### Summary Unauthenticated users can upload any amount of data to the server without any limitations. No need for any prior knowledge, only network access to Langflow. This can lead to space exhaustion on the server. In adition, in the response, the absolute path of the uploaded file is reported to the attacker, which is an information leak that can assist in chaining other primitives. Tested on commit 2d67402b1dbaefcbce85a244d4a6cd5e4bda1cfe ### Details Code is in `langflow/api/v1/[endpoints.py](http://endpoints.py/)`: ```python @router.post( "/upload/{flow_id}", status_code=HTTPStatus.CREATED, deprecated=True, ) async def create_upload_file( file: UploadFile, flow_id: UUID, ) -> UploadFileResponse: ... ``` As can be seen above, there is no authentication. There is not validation over `flow_id` as well, unlike other endpoints: ``` flow_id_str = str(flow_id) file_path = await asyncio.to_thread(save_uploaded_file, file, folder_name=flow_id_str) ``` Function `save_uploaded_file` saves the file to local file-system. Suggested fix: 1. Add authentication to route. 2. Only return relative path or filename. ### PoC PoC: ```bash curl 'http://localhost:7860/api/v1/upload/<any_uuid>' -F "file=@<any_file>" ``` Example: ```bash # curl 'http://localhost:7860/api/v1/upload/11111111-1111-1111-1111-111111111111' -F "file=@/tmp/dummy.txt" {"flowId":"11111111-1111-1111-1111-111111111111","file_path":"/Users/ori/Library/Caches/langflow/11111111-1111-1111-1111-111111111111/9d63c3b5b7623d1fa3dc7fd1547313b9546c6d0fbbb6773a420613b7a17995c8.txt"} ``` ### Impact 1. Space exhaustion on server that can lead to Denial-of-Service. 2. Information leak - leakage of absolute path of langflow's cache directory in server. ### Patches Fixed in **1.9.1** via PR [#12831](https://github.com/langflow-ai/langflow/pull/12831). The deprecated `POST /api/v1/upload/{flow_id}` endpoint now uses the `get_flow` dependency, requiring an authenticated user and flow ownership (returns `404` for missing or cross-user flows), and enforces the `max_file_size_upload` limit (`HTTP 413`) — closing the unauthenticated upload and disk-exhaustion vectors. Upgrade to **1.9.1 or later**. Note: the response still returns the file's absolute path (`file_path`); after this fix it is only disclosed to the authenticated owner of the flow. Ori Lahav Security Researcher @ Rubrik Inc.
Update langflow to 1.9.1 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanLangflow: Unauthenticated file upload leads to DoS (space exhaustion) and information leak affects langflow (pip). Severity is critical. ### Summary Unauthenticated users can upload any amount of data to the server without any limitations. No need for any prior knowledge, only network access to Langflow. This can lead to space exhaustion on the server. In adition, in the response, the absolute path of the uploaded file is reported to the attacker, which is an information leak that can assist in chaining other primitives. Tested on commit 2d67402b1dbaefcbce85a244d4a6cd5e4bda1cfe ### Details Code is in `langflow/api/v1/[endpoints.py](http://endpoints.py/)`: ```python @router.post( "/upload/{flow_id}", status_code=HTTPStatus.CREATED, deprecated=True, ) async def create_upload_file( file: UploadFile, flow_id: UUID, ) -> UploadFileResponse: ... ``` As can be seen above, there is no authentication. There is not validation over `flow_id` as well, unlike other endpoints: ``` flow_id_str = str(flow_id) file_path = await asyncio.to_thread(save_uploaded_file, file, folder_name=flow_id_str) ``` Function `save_uploaded_file` saves the file to local file-system. Suggested fix: 1. Add authentication to route. 2. Only return relative path or filename. ### PoC PoC: ```bash curl 'http://localhost:7860/api/v1/upload/<any_uuid>' -F "file=@<any_file>" ``` Example: ```bash # curl 'http://localhost:7860/api/v1/upload/11111111-1111-1111-1111-111111111111' -F "file=@/tmp/dummy.txt" {"flowId":"11111111-1111-1111-1111-111111111111","file_path":"/Users/ori/Library/Caches/langflow/11111111-1111-1111-1111-111111111111/9d63c3b5b7623d1fa3dc7fd1547313b9546c6d0fbbb6773a420613b7a17995c8.txt"} ``` ### Impact 1. Space exhaustion on server that can lead to Denial-of-Service. 2. Information leak - leakage of absolute path of langflow's cache directory in server. ### Patches Fixed in **1.9.1** via PR [#12831](https://github.com/langflow-ai/langflow/pull/12831). The deprecated `POST /api/v1/upload/{flow_id}` endpoint now uses the `get_flow` dependency, requiring an authenticated user and flow ownership (returns `404` for missing or cross-user flows), and enforces the `max_file_size_upload` limit (`HTTP 413`) — closing the unauthenticated upload and disk-exhaustion vectors. Upgrade to **1.9.1 or later**. Note: the response still returns the file's absolute path (`file_path`); after this fix it is only disclosed to the authenticated owner of the flow. Ori Lahav Security Researcher @ Rubrik Inc.
AI coding agents often install or upgrade packages automatically in pip. A critical vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| langflowpip | <1.9.1 | 1.9.1 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL GuardUpdate langflow to 1.9.1 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanLangflow: Unauthenticated file upload leads to DoS (space exhaustion) and information leak affects langflow (pip). Severity is critical. ### Summary Unauthenticated users can upload any amount of data to the server without any limitations. No need for any prior knowledge, only network access to Langflow. This can lead to space exhaustion on the server. In adition, in the response, the absolute path of the uploaded file is reported to the attacker, which is an information leak that can assist in chaining other primitives. Tested on commit 2d67402b1dbaefcbce85a244d4a6cd5e4bda1cfe ### Details Code is in `langflow/api/v1/[endpoints.py](http://endpoints.py/)`: ```python @router.post( "/upload/{flow_id}", status_code=HTTPStatus.CREATED, deprecated=True, ) async def create_upload_file( file: UploadFile, flow_id: UUID, ) -> UploadFileResponse: ... ``` As can be seen above, there is no authentication. There is not validation over `flow_id` as well, unlike other endpoints: ``` flow_id_str = str(flow_id) file_path = await asyncio.to_thread(save_uploaded_file, file, folder_name=flow_id_str) ``` Function `save_uploaded_file` saves the file to local file-system. Suggested fix: 1. Add authentication to route. 2. Only return relative path or filename. ### PoC PoC: ```bash curl 'http://localhost:7860/api/v1/upload/<any_uuid>' -F "file=@<any_file>" ``` Example: ```bash # curl 'http://localhost:7860/api/v1/upload/11111111-1111-1111-1111-111111111111' -F "file=@/tmp/dummy.txt" {"flowId":"11111111-1111-1111-1111-111111111111","file_path":"/Users/ori/Library/Caches/langflow/11111111-1111-1111-1111-111111111111/9d63c3b5b7623d1fa3dc7fd1547313b9546c6d0fbbb6773a420613b7a17995c8.txt"} ``` ### Impact 1. Space exhaustion on server that can lead to Denial-of-Service. 2. Information leak - leakage of absolute path of langflow's cache directory in server. ### Patches Fixed in **1.9.1** via PR [#12831](https://github.com/langflow-ai/langflow/pull/12831). The deprecated `POST /api/v1/upload/{flow_id}` endpoint now uses the `get_flow` dependency, requiring an authenticated user and flow ownership (returns `404` for missing or cross-user flows), and enforces the `max_file_size_upload` limit (`HTTP 413`) — closing the unauthenticated upload and disk-exhaustion vectors. Upgrade to **1.9.1 or later**. Note: the response still returns the file's absolute path (`file_path`); after this fix it is only disclosed to the authenticated owner of the flow. Ori Lahav Security Researcher @ Rubrik Inc.
AI coding agents often install or upgrade packages automatically in pip. A critical vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| langflowpip | <1.9.1 | 1.9.1 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL Guard