Now that v1.5.0 has shipped, 1.4.x moves to security-fix-only support for one minor cycle (until v1.6.0); operators should plan migration to v1.5 within that window. The current minor + one back is always supported; older minors get security-only patches for one cycle, then EOL.

CVE IDs are requested at publish time and attached to the GHSA when GitHub Security Lab assigns them (typically 1-7 days post-publication).

If you discover a security vulnerability, please report it responsibly:

1. Do NOT open a public GitHub issue — the report is visible to anyone the moment it's filed.
2. Open a private security advisory via GitHub's Security tab.
3. Or email the maintainer directly if the GitHub flow is blocked for you.

Email: 64996768+mcp-tool-shop@users.noreply.github.com

When reporting, please include:

• The run_id (printed at startup as run_started run_id=<uuid>, also exposed as TrainingRun.run_id / RunResult.run_id) if the issue surfaced during a training run. One UUID lets the maintainer correlate every log line, checkpoint, and SLAO merge for that exact run — without it, reproducing your timeline is much harder.
• The structured error code (e.g. [INPUT_AUTH_REQUIRED], [UI_OUTPUT_DIR_FORBIDDEN]) if one was emitted. The catalog at handbook/error-codes lists every stable code.
• A minimal reproduction. Stderr in non-verbose mode is automatically redacted (Bearer / sk-* / hf_* / AWS keys, password=/token=/api_key= pairs) — safe to paste. For the full unredacted trace, re-run with --verbose (or BACKPROPAGATE_DEBUG=1) and review the output for any remaining secrets before posting.

• Acknowledgment: within 48 hours.
• Assessment: within 1 week — severity, scope, and a rough patch ETA.
• Fix: based on severity (Critical: hot-patch release; High: next patch; Medium/Low: next minor).
• Disclosure: GHSA publication coordinated with the reporter; CVE IDs requested at publish (typically 1–7 days post-publication, see existing advisories for examples).

• Never commit API keys or tokens
• Validate training data sources
• Keep dependencies updated
• When using backprop ui, do not pass --share without --auth (and on v1.1.x, do not pass either — see GHSA-f65r-h4g3-3h9h above; upgrade to v1.2.0). In v1.2.0+, --share without --auth hard-errors with RUNTIME_UI_AUTH_NOT_ENFORCED. For remote access without exposing the UI publicly, use SSH port-forwarding: ssh -L 7860:localhost:7860 <training-host> then open http://localhost:7860 locally.
• The UI sandboxes filesystem writes to a single base directory (~/.backpropagate/ui-outputs by default; override via BACKPROPAGATE_UI__OUTPUT_DIR). The override is denylist-validated — system / credential paths are refused with [UI_OUTPUT_DIR_FORBIDDEN].