| Component | LangChain |
| Severity | high (CVSS 7.5) |
| CVSS vector | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| Published (NVD) | 2025-03-20 |
| Last modified | 2026-06-17 |
| Affected versions | llamaindex = 0.12.5 |
| Fixed in | see the vendor advisory |
| Weakness | CWE-835 |
| CISA KEV | not listed |
NVD description
A vulnerability in the LangChainLLM class of the run-llama/llama_index repository, version v0.12.5, allows for a Denial of Service (DoS) attack. The stream_complete method executes the llm using a thread and retrieves the result via the get_response_gen method of the StreamingGeneratorCallbackHandler class. If the thread terminates abnormally before the _llm.predict is executed, there is no exception handling for this case, leading to an infinite loop in the get_response_gen function. This can be triggered by providing an input of an incorrect type, causing the thread to terminate and the process to continue running indefinitely.
What to do
- NVD lists no fixed version yet: follow the vendor advisory below and keep LangChain off the public internet until a fix ships.
- Do not expose the component's API or UI to the internet without authentication in front of it.
Sources
- NVD: CVE-2024-12704
- https://github.com/run-llama/llama_index/commit/d1ecfb77578d089cbe66728f18f635c09aa32a05
- https://huntr.com/bounties/a0b638fd-21c6-4ba7-b381-6ab98472a02a
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