A maximum-severity remote code execution flaw in ChromaDB's Python FastAPI server, tracked as CVE-2026-45829, allows unauthenticated attackers to take over exposed instances by abusing an API endpoint that fetches and executes attacker-controlled model code from Hugging Face before authentication is enforced. HiddenLayer, which disclosed the issue under the name ChromaToast Served Pre-Auth, reported the bug to ChromaDB after finding that the vulnerable server-side code was introduced in version 1.0.0 and remained present through at least 1.5.8, with the status of 1.5.9 unclear.
The exposure is significant for AI application environments using ChromaDB as a vector database: HiddenLayer said about 73% of internet-exposed Chroma instances identified via Shodan appeared to be running vulnerable versions. Deployments using ChromaDB locally without exposing the API server, or using the Rust front-end instead of the Python server, are not affected. Recommended mitigations include removing public access to the Python API server, restricting network access to the ChromaDB port, preferring the Rust front-end where possible, and scanning machine learning model artifacts before runtime.

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BleepingComputer reported that CVE-2026-45829 remained unpatched in ChromaDB version 1.5.8, with uncertainty around whether version 1.5.9 fixed it. The report highlighted HiddenLayer's estimate that about 73% of internet-exposed Chroma instances found via Shodan were running vulnerable versions and recommended limiting exposure or using the Rust frontend.
HiddenLayer publicly disclosed research on the ChromaDB vulnerability, describing a pre-authentication remote code execution issue in exposed Python API server deployments. The disclosure noted the issue affected server code introduced in version 1.0.0 and that many internet-exposed instances appeared vulnerable.
HiddenLayer reported CVE-2026-45829 to ChromaDB on 2026-02-17. The flaw affects ChromaDB's Python FastAPI server and can allow unauthenticated remote code execution via attacker-controlled model code loaded from Hugging Face before authentication is enforced.
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