Blexch (b1exch.to) Bug Bounty: $5,000 Each Validated Critical — Full Scope, Kill Chain Required

Blexch inherits classic CEX risk: sessions, API keys, order and margin state, withdraw races, admin consoles — $5,000 per demonstrated critical.

In scope: b1exch.to and delegated hosts.
Exclusions: crime / laundering / harassment — not SKU fences.

There is exactly one bounty amount on this ledger: validated critical findings pay $5,000 USD each. Novel low-severity items may qualify for goodwill credit but not this stipend. Paid rows require attacker-readable kill chains and replayable exploitation artefacts (Burp exports, parallel withdraw harnesses, WS replay dumps, signing traces…).

Rows below do not cap surface. Anything Blexch hosts, signs, matches, settles, or withdraws through counts as bounty ground. “Not listed” ≠ “out-of-scope.”

Sandbox books or pool clusters, Grafana, bot hooks for risk alerts, partner APIs fronted by Blexch — all eligible when critical impact reproduces.

• Vanity domains CNAME’d into Blexch edge — show DNS/traffic proof in your write-up.
• Wallet connector SDKs or bookmarklets Blexch ships
• Colocated market-making or liquidity pool containers they operate
• Bridge, on-ramp, or pool callbacks verified with Blexch-issued secrets

1. Prove exploitation success. Provide scripts, HARs, parallel request captures, or signing traces showing fund/state impact — not paper analysis alone.
2. Number your hops. Session/API primitive → escalation → treasury or book integrity break.
3. Minimize real-user blast radius. Prefer mirrors, low-value accounts, and reversible payloads when demonstrating theft-class bugs.
4. Private coordination first. Use official intake on b1exch.to before public threads.
5. Duplicate fairness. First qualifying PoC wins; followers close acknowledged-only.

Use the security / vulnerability disclosure contact published on https://b1exch.to/ (security@b1exch.to is a common guess — verify on the live site before emailing). Template below.

# Title
[Critical][Exploit-Proven] <tight title>

# Executive summary — trader/treasury impact in one paragraph

# Severity self-classification → must map to Blexch critical definitions above

## Attack chain narrative (numbered, no gaps)
1. Preconditions (session, API key tier, market symbol, account ID)
2. Entry primitive — HTTP/WS line + signature headers
3. Pivot(s) → privilege/order/withdraw escalation
4. Final hop → balance theft / forged payout / infra takeover equivalent

## Successful exploitation evidence
• Scripted replay showing ledger/withdraw impact
• Parallel request traces (race/double-spend)
• Custody or admin log lines proving attacker-forged intent accepted

## Reproduction package
Commands + fixtures + commit/patch SHAs

## Disclosure ack
Private channel only until Blexch clears publication

Illustrative parallel withdraw — prove on b1exch.to.

// BUGGY: non-atomic balance check + debit — parallel wins double payout
async function requestWithdraw(userId, amount) {
  const bal = await db.getBalance(userId);
  if (bal < amount) throw new Error('insufficient');
  await db.debit(userId, amount);
  await queue.enqueuePayout(userId, amount);
}