Will JonesandClaude Opus 5.5
9020640538
BREAKING CHANGE: `SentenceTransformerEmbeddings.trust_remote_code` now
defaults to `False` (was `True`). When an embedding function is restored
from table metadata, `trust_remote_code=True` and custom endpoints
(OpenAI `base_url`, Ollama `host`/proxy, watsonx `url`) are only honored
if the process approved them; otherwise computing embeddings raises
`UntrustedEmbeddingConfigError`. Functions created in the same process
are approved automatically. To reopen such a table in a new process,
call `get_registry().allow_remote_code(model, revision=...)` or
`get_registry().allow_endpoint(url)` first.
## Summary
Embedding functions are rebuilt from table metadata, which anyone who
can write the table controls. Since sentence-transformers defaulted
`trust_remote_code` to `True`, opening and querying a crafted table ran
arbitrary code from a model repository (GHSA-x8v2-vj73-gfwm). Metadata
could likewise point `base_url` at another server, sending it queries
and the `OPENAI_API_KEY` from the environment.
The table can no longer grant itself trust:
```python
registry = get_registry()
registry.allow_remote_code("nomic-ai/nomic-embed-text-v1.5", revision="<commit>")
registry.allow_endpoint("http://my-ollama-host:11434")
```
Trust is keyed by model name (optionally pinned to a revision), so
approving one model doesn't let a table swap in another. Restored
functions that aren't approved are replaced by a placeholder that raises
on use without constructing the real function (`huggingface` loads its
model in `__init__`), so non-embedding operations on the table keep
working. `sentence-transformers` and `huggingface` gain a `revision`
parameter. Custom embedding functions can opt in by overriding the new
`remote_code_model()` / `endpoints()` hooks.
Not covered: TypeScript (its built-ins have neither remote code nor
configurable endpoints), Bedrock `assumed_role`, and third-party
functions that don't implement the hooks.
## Evidence
`test_embeddings_trust.py` covers restore with and without approval,
revision pinning, swapped model names, endpoint gating, and that the
table stays usable. Opening a table with crafted metadata and searching
it now gives:
```
UntrustedEmbeddingConfigError: Embedding function 'sentence-transformers' was restored from table metadata with settings this process has not approved:
- runs code from model 'attacker/model' at revision None. If you trust it, call get_registry().allow_remote_code('attacker/model', revision=None)
```
## Merge Risk
**Door:** One-way: changes a default and makes previously working
reopen-and-search flows require explicit approval.
**Blast Radius:** public-api (Python embeddings); users of remote-code
models or custom endpoints who reopen tables in a new process.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
LanceDB Python SDK
A Python library for LanceDB.
Installation
pip install lancedb
Pre-Haswell x86_64 hosts: lancedb-compat
The default lancedb wheel targets x86-64-haswell (AVX2 + FMA + F16C) for full performance on modern hardware. Pre-Haswell hosts — Intel Sandy Bridge / Ivy Bridge / Westmere; AMD Bulldozer / Piledriver / Steamroller — don't have AVX2 and crash with Illegal instruction at import lancedb.
For those hosts, install the lancedb-compat package instead:
pip install lancedb-compat
Same Python API (import lancedb works as usual). The compat wheel is compiled at the x86-64-v2 baseline (Nehalem-class) and uses runtime SIMD dispatch in the embedded lance crate to pick the right kernel tier (scalar / AVX / AVX+FMA / AVX2+FMA / AVX-512) at load time, so it still goes fast on modern hardware while running cleanly on the pre-Haswell silicon. Use lance.simd_info() from Python to verify which tier was selected.
lancedb and lancedb-compat install to the same lancedb/ namespace and conflict at install time. Pick one. To switch, pip uninstall lancedb first, then pip install lancedb-compat (or vice-versa).
If you need a custom baseline (or lancedb-compat isn't yet published for your platform), build from source with the override:
RUSTFLAGS="-C target-cpu=x86-64-v2" maturin build --release
pip install ./target/wheels/lancedb-*.whl
Preview Releases
Stable releases are created about every 2 weeks. For the latest features and bug fixes, you can install the preview release. These releases receive the same level of testing as stable releases, but are not guaranteed to be available for more than 6 months after they are released. Once your application is stable, we recommend switching to stable releases.
pip install --pre --extra-index-url https://pypi.fury.io/lancedb/ lancedb
Threading in CPU-limited containers
LanceDB uses separate pools for compute work and storage I/O. On a container with two visible CPUs, current releases intentionally use one compute worker by default; no manual configuration is needed. If every query logs an I/O core reservation warning on a two-CPU container, upgrade from LanceDB 0.21.1 or earlier.
The two commonly tuned environment variables control different resources:
LANCE_CPU_THREADSoverrides the number of compute workers. One worker is the appropriate setting for a two-CPU container when an explicit override is needed.LANCE_IO_THREADScontrols concurrent storage operations, not reserved CPU cores. Its default can be greater than the number of CPUs because I/O workers spend much of their time waiting for storage.
Keep the defaults unless measurements show that the workload benefits from an override. See the Lance threading model for the current defaults and tuning guidance.
Usage
Basic Example
import lancedb
db = lancedb.connect('<PATH_TO_LANCEDB_DATASET>')
table = db.open_table('my_table')
results = table.search([0.1, 0.3]).limit(20).to_list()
print(results)
Development
See CONTRIBUTING.md for information on how to contribute to LanceDB.