Flyto2 Core is an execution kernel for automation and AI-agent workflows. Prior to 2.26.7, the standalone flyto-verification service in src/core/verification_service.py exposes unauthenticated POST /run on 0.0.0.0:8344 and uses client-supplied callback_url for an outbound POST with X-Internal-Key: $FLYTO_RUNNER_SECRET while bypassing target_allowed, allowing unauthenticated SSRF and runner secret exfiltration. This issue is fixed in version 2.26.7.

Affected: PyPI: flyto-core

## Summary The standalone `flyto-verification` service exposes `POST /run` with **no authentication**, on all interfaces (0.0.0.0:8344 per the shipped Dockerfile). The request body's `callback_url` is used verbatim for an outbound POST that **unconditionally attaches `X-Internal-Key: $FLYTO_RUNNER_SECRET`**. The `callback_url` bypasses the service's `target_allowed` allowlist (which only inspects `params.target_url`) and is never passed through any SSRF guard. This yields (a) unauthenticated SSRF to internal/metadata endpoints with an attacker-controlled JSON body, and (b) exfiltration of the internal runner secret to an attacker-controlled host — allowing forged authenticated callbacks to the real engine.

## Root Cause - `src/core/verification_service.py:363-364` — `/run` has no `Depends`/auth dependency. - `resolve_callback_url` returns the client `callback_url` verbatim (`:315-316`). - `post_callback` attaches `X-Internal-Key: $FLYTO_RUNNER_SECRET` whenever the env var is set (`:327-335`). - `target_allowed` only gates `params.target_url` (`:259`), never `callback_url`. No `validate_url_*` anywhere in the file. - `Dockerfile.verification` CMD = `main('0.0.0.0', 8344)`; entrypoint `flyto-verification` in `pyproject.toml:107` → the shipped image binds all interfaces by default.

## Impact Unauthenticated (PR:N) readable SSRF to internal/cloud-metadata with a controlled body (C:H, S:C), plus theft of `FLYTO_RUNNER_SECRET` to an attacker host → the attacker can then authenti…

Affected: PyPI: flyto-core

## Summary The standalone `flyto-verification` service exposes `POST /run` with **no authentication**, on all interfaces (0.0.0.0:8344 per the shipped Dockerfile). The request body's `callback_url` is used verbatim for an outbound POST that **unconditionally attaches `X-Internal-Key: $FLYTO_RUNNER_SECRET`**. The `callback_url` bypasses the service's `target_allowed` allowlist (which only inspects `params.target_url`) and is never passed through any SSRF guard. This yields (a) unauthenticated SSRF to internal/metadata endpoints with an attacker-controlled JSON body, and (b) exfiltration of the internal runner secret to an attacker-controlled host — allowing forged authenticated callbacks to the real engine.

## Root Cause - `src/core/verification_service.py:363-364` — `/run` has no `Depends`/auth dependency. - `resolve_callback_url` returns the client `callback_url` verbatim (`:315-316`). - `post_callback` attaches `X-Internal-Key: $FLYTO_RUNNER_SECRET` whenever the env var is set (`:327-335`). - `target_allowed` only gates `params.target_url` (`:259`), never `callback_url`. No `validate_url_*` anywhere in the file. - `Dockerfile.verification` CMD = `main('0.0.0.0', 8344)`; entrypoint `flyto-verification` in `pyproject.toml:107` → the shipped image binds all interfaces by default.

## Impact Unauthenticated (PR:N) readable SSRF to internal/cloud-metadata with a controlled body (C:H, S:C), plus theft of `FLYTO_RUNNER_SECRET` to an attacker host → the attacker can then authenti…