mistral.rs media loader SSRF and arbitrary file read via image_url

Severity: high · CVSS 7.2 · Published 2026-09-10

mistral.rs is an open-source LLM inference server that includes a vision/audio model capability accepting media URLs in chat requests. An unauthenticated attacker can exploit the media loader to send requests to internal or cloud-metadata services (SSRF), and to probe the server filesystem for file existence, as the server performs no validation of supplied URLs or paths. While the attack does not expose file contents, it enables reconnaissance and potential access to internal service metadata.

Technologies: EricLBuehler Mistral.Rs. Vendors: crates.io, EricLBuehler.

Quick answers

Is This vulnerability exploited in the wild?
No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.
How severe is This vulnerability?
High severity, with a CVSS score of 7.2, published 10 September 2026.
Which products and versions are affected?
mistralrs-server-core (crates.io) <= 0.8.17; EricLBuehler Mistral.Rs <= 0.8.17.
Is there a fix for This vulnerability?
A patch was published on 2026-09-10: Version 0.8.18 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is This vulnerability attacked?
It is attacked over the network, in a software library.
Am I affected?
Check whether you run mistralrs-server-core (crates.io) or EricLBuehler Mistral.Rs at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability exists in the `parse_image_url` and `parse_audio_url` functions in mistralrs-server-core/src/util.rs, which process user-supplied media URLs from OpenAI-compatible `/v1/chat/completions` requests without validation. The vulnerable code resolves any supplied URL string, attempts to fetch http(s) URLs via `reqwest::get()` with no IP allowlist or private-IP blocking, and opens file:// URLs or any existing local filesystem path. The http(s) branch has no timeout, reads unbounded response bodies, and follows redirects by default; the file branch allocates full file size in memory before reading. An attacker with network access to a default (unauthenticated) deployment can trigger SSRF to internal services and cloud metadata endpoints, and can use differential error messages to enumerate filesystem entries (existing file returns "image format could not be determined"; nonexistent path returns "file not found on server"). The SSRF is blind (fetched bytes go to a media decoder, not to the attacker), but enables egress to internal hosts. Availability is impacted by unbounded request/file handling. Patch 0.8.18 restricts media to http(s) and data: schemes, validates IP addresses before fetching, disables file:// access, and caps read sizes.

Affected products

  • EricLBuehler mistral.rs <= 0.8.17

Timeline

  • 2026-06-21: disclosed
  • 2026-09-10: advisory
  • 2026-09-10: patched: Version 0.8.18 released

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.