Package Instance

Ray dashboard DELETE endpoints allow unauthenticated browser-triggered DoS (Serve shutdown / job deletion)
Ray’s dashboard HTTP server blocks browser-origin POST/PUT but does not cover DELETE, and key DELETE endpoints are unauthenticated by default. If the dashboard/agent is reachable (e.g., --dashboard-host=0.0.0.0), a web page via DNS rebinding or same-network access can
issue DELETE requests that shut down Serve or delete jobs without user interaction. This is a drive-by availability impact.

Ray is vulnerable to Critical RCE via Safari & Firefox Browsers through DNS Rebinding Attack
Developers working with Ray as a development tool can be exploited via a critical RCE vulnerability exploitable via Firefox and Safari.

Due to the longstanding [decision](https://docs.ray.io/en/releases-2.51.1/ray-security/index.html) by the Ray Development team to not implement any sort of authentication on critical endpoints, like the `/api/jobs` & `/api/job_agent/jobs/` has once again led to a severe vulnerability that allows attackers to execute arbitrary code against Ray. This time in a development context via the browsers Firefox and Safari.

This vulnerability is due to an insufficient guard against browser-based attacks, as the current defense uses the `User-Agent` header starting with the string "Mozilla" as a defense mechanism. This defense is insufficient as the fetch specification allows the `User-Agent` header to be modified.

Combined with a DNS rebinding attack against the browser, and this vulnerability is exploitable against a developer running Ray who inadvertently visits a malicious website, or is served a malicious advertisement ([malvertising](https://en.wikipedia.org/wiki/Malvertising)).

Ray: Remote Code Execution via Parquet Arrow Extension Type Deserialization
Ray Data registers custom Arrow extension types (`ray.data.arrow_tensor`, `ray.data.arrow_tensor_v2`, `ray.data.arrow_variable_shaped_tensor`) globally in PyArrow. When PyArrow reads a Parquet file containing one of these extension types, it calls `__arrow_ext_deserialize__` on the field's metadata bytes. Ray's implementation passes these bytes directly to `cloudpickle.loads()`, achieving arbitrary code execution during schema parsing, before any row data is read.

In May 2024, Ray fixed a related vulnerability in `PyExtensionType`-based extension types ([issue #41314](https://github.com/ray-project/ray/issues/41314), [PR #45084](https://github.com/ray-project/ray/pull/45084)). In July 2025, [PR #54831](https://github.com/ray-project/ray/pull/54831) introduced `cloudpickle.loads()` into the replacement extension types' deserialization path, reintroducing the same class of vulnerability.

## Impact

- **Affected versions**: Ray 2.49.0 through 2.54.0 (latest release as of March 2026). The vulnerable `_deserialize_with_fallback` function with `cloudpickle.loads()` was introduced in commit `f6d21db1a4` ([PR #54831](https://github.com/ray-project/ray/pull/54831), July 2025), first released in Ray 2.49.0.
- **Affected configurations**: Any process that uses Ray Data and reads Parquet files. The extension types are registered globally in PyArrow, so all Parquet reads in the process are affected, including `ray.data.read_parquet()`, `pyarrow.parquet.read_table()`, `pandas.read_parquet()`, etc.
- **Attacker prerequisites**: The attacker must place a crafted Parquet file where a Ray Data pipeline reads it. No authentication or cluster access is required. The Parquet file must contain a column with a `ray.data.arrow_tensor` (or v2, or variable-shaped) extension type name, which makes this a targeted attack against Ray Data users.

Ray's New Token Authentication is Disabled By Default
Anyscale Ray 2.52.0 contains an insecure default configuration in which token-based authentication for Ray management interfaces (including the dashboard and Jobs API) is disabled unless explicitly enabled by setting RAY_AUTH_MODE=token. In the default unauthenticated state, a remote attacker with network access to these interfaces can submit jobs and execute arbitrary code on the Ray cluster. NOTE: The vendor plans to enable token authentication by default in a future release. They recommend enabling token authentication to protect your cluster from unauthorized access.

Ray has arbitrary code execution via jobs submission API
Anyscale Ray allows a remote attacker to execute arbitrary code via the job submission API. NOTE: the vendor's position is that this report is irrelevant because Ray, as stated in its documentation, is not intended for use outside of a strictly controlled network environment.