Add advisory for physis_pro: remote error body can permanently disable a shared LLM provider

[ilPez00]

Filed by the crate author, which per CONTRIBUTING waives the upstream-report and coordinated-disclosure prerequisites. The embargo is lifted: the fix, the affected range and the mechanism are already public in the crate's own repository and changelog.

Summary. physis_pro routes completions through a cascade of LLM providers. In 0.1.6–0.1.8 a provider was removed from the cascade by substring-matching the text of a failed HTTP response. OpenAI-compatible endpoints quote the offending request back inside error.message, and that request carries the caller's prompt — so a prompt containing a phrase like does not exist that provokes any 4xx would match. The removal was permanent (mark_unavailable() wrote a flag only Provider::new() ever cleared) and the cascade is process-wide, so the loss hit every caller rather than the one who caused it. Walking the cascade reaches No provider available for the life of the process.

Availability only — no disclosure or modification of data. Rated AC:H because success depends on the upstream provider echoing request content in its error bodies: common among OpenAI-compatible gateways, but a property of the vendor rather than of this crate.

Fixed in 0.1.9. Detection now reads only the machine-written error.code / error.type fields against a fixed set of vendor codes, never the message prose, and skips bodies that are not JSON. The park became a bounded 15-minute cooldown rather than a permanent latch.

Versions. patched = [">= 0.1.9"], unaffected = ["< 0.1.6"]. The lower bound was taken from the published tarballs rather than from git history — 0.1.5 carries only a pre-existing 401/403 latch, which keys on a status code rather than on caller-influenced text, so it is not vulnerable. 0.1.6, 0.1.7 and 0.1.8 have been yanked.

rustsec-admin lint reports Linted ok for this file.

Full write-up: https://github.com/ilPez00/physis-pro/blob/main/security/advisories/physis_pro-provider-availability.md

[djc]

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