xchain-sdk is the developer SDK for generating XChain actions, and includes an MCP server (xchain-mcp, entry point mcp/cli.js) for tool-based integrations. Downstream applications and wallets use it to construct and sign actions, so a flaw can cause a consumer to build a wrong or fund-losing transaction. The published browser bundle (dist/xchain_sdk.min.js, produced by npm run build) extends that surface to browser clients. We treat security reports seriously and respond fast.

If you've found a security issue, please do not open a public issue or pull request. Use the private channels below.

Open a draft advisory at:

https://github.com/XChain-Platform/xchain-sdk/security/advisories/new

This is the fastest path. The advisory is private until we publish it.

Email security@dankest.llc with:

• A description of the issue and the threat it poses.
• Reproduction steps or a proof-of-concept (a crafted input, action call, or payload that triggers the bug).
• The affected version (see CHANGELOG.md and the version badge in README.md) and the network you tested against (mainnet / testnet / regtest, and which chain).
• Any patches or mitigations you'd like considered.

For sensitive reports, encrypt the email body to our PGP key. The fingerprint will be published alongside the first signed release artifact; until then, the email channel is acceptable for first contact and we will coordinate an encrypted exchange before you share proof-of-concept details.

We do not currently offer a paid bug bounty. We do offer public credit in release notes and the advisory itself, unless you prefer to remain anonymous.

If we cannot meet a timeline, we will tell you why and propose a new one. We will not silently let a report age.

• Correctness of action generation and encoding helpers in src/ (wrong action string, wrong amount, misdirected destination, format-version misselection).
• The MCP server surface (mcp/cli.js, exposed as the xchain-mcp binary): tool definitions, parameter handling, any path where a tool call could produce a wrong or fund-losing action.
• Guidance or handling around key material in SDK consumers: any API that inadvertently leaks, logs, or mishandles private keys or WIF values.
• The browser bundle (dist/xchain_sdk.min.js) built by npm run build, including supply-chain integrity of that artifact and its Browserify/Babel build pipeline.
• Any path where a malformed or adversarial input to the SDK yields a valid-looking but incorrect transaction.

• Bugs in applications built on the SDK that misuse its API (that is the application author's responsibility, not an SDK vulnerability).
• The user's key custody and signing environment.
• Vulnerabilities in the underlying chains.
• Compromise of upstream npm dependencies (we mitigate via audit + review, but a backdoor in a dep is the dep author's incident, though we still want to hear about it).
• Misconfiguration of the operator's own service endpoints or network exposure.

If you are unsure, send the report anyway and we will tell you whether it falls in scope.

• Give us a reasonable window to fix before disclosing publicly. The 90-day ceiling is firm; earlier is fine once a fix has shipped and operators are protected.
• Test against regtest or testnet where possible (the xchain-regtest-miner plus a local stack make this easy). Mainnet proofs-of-concept are accepted but should be the minimum needed.
• Do not run automated scanners against shared XChain infrastructure in a way that would impact availability for other operators.
• Do not access data, or attempt to access data, beyond what is needed to demonstrate the issue.

• Confirm receipt within the SLA above.
• Keep you informed as triage and remediation proceed.
• Credit you in the advisory and CHANGELOG.md entry, on request.
• Coordinate a CVE assignment when the severity warrants it.
• Publish a post-fix advisory describing the issue, the fix, and the affected version range.

We ship security fixes against the latest release on master. Older releases are unsupported. The current version is recorded in CHANGELOG.md and the badge in README.md.

Last reviewed: 2026-06-16.