xchain-utxo-tracker indexes all UTXOs from a coin node and serves address and balance queries over a REST and JSON-RPC API (LevelDB-backed). The encoder depends on this service to select spendable inputs when constructing transactions: a wrong or stale balance can lead to a malformed or fund-losing transaction. We treat 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-utxo-tracker/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 query, block, or chain state 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 UTXO and balance accounting in src/ (output indexing, spend tracking, balance aggregation, BigInt arithmetic).
• Reorg and desync handling: the undo history (sized per chain and per network by DEFAULT_UNDO_BLOCKS in src/chain/undo_blocks.js), rollback logic, and any path where a chain reorganization can leave the index in an inconsistent state that produces wrong balances.
• The address and balance query API (REST and JSON-RPC): injection via query parameters, response correctness, and any path that returns wrong balances to the encoder.
• Denial-of-service or memory exhaustion via crafted queries, large address sets, or abnormal chain data (the service runs with --max-old-space-size=4096; unbounded growth is in scope).
• Mempool tracking correctness: unconfirmed outputs in the in-memory LevelDB and any race between mempool state and confirmed-block state.
• Bootstrap backup and restore integrity: a tampered or truncated archive that causes the tracker to serve incorrect state after a restore.
• Any path that returns wrong balances to a caller, since those balances flow directly into transaction construction by the encoder.

• How the encoder uses the balances it receives (report against xchain-encoder).
• Vulnerabilities in the underlying coin node (bitcoind / litecoind / dogecoind); report those to their respective projects.
• 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 host, LevelDB paths, or network exposure (for example, binding the API to a public interface without a firewall).
• Attacks that require the operator's shell access to the tracker host.

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.