---
title: "Some Miners Generating Invalid Blocks"
alias: "spv-mining"
active: true
banner: "WARNING: many wallets currently vulnerable to double-spending of confirmed transactions (click here to read)"
---

<p><em>This document is being updated as new information arrives.  Last
update: 2015-07-04 06:00 UTC</em></p>

<h2 id="summary">Summary</h2>

<p>Some miners are currently generating invalid blocks. <b>Bitcoin Core
   0.9.4 and earlier</b> will accept these invalid blocks, making them
   more vulnerable to double spends.  This <b>also applies to web wallets</b>
   from companies that still use 0.9.4 or earlier nodes.</p>

<p><b>Lightweight (SPV) wallets are also at increased risk,</b> and will
      remain so until all miners have switched back to full
      validation.</p>

<p>Users of the above listed vulnerable software must either <b>stop
   accepting transactions—even if they are confirmed—</b>or <a href="/en/download">upgrade to Bitcoin
   Core 0.10.2</a>.</p>

<p>Users of Bitcoin Core 0.9.5 and later are currently unaffected.</p>

<h2 id="miners">Miners</h2>

If you pool mine, please switch to a pool that properly validates
blocks.  (If you solo mine, please switch to Bitcoin Core 0.10.2.)

<p><b>Bad pools:</b> these pools are not correctly validating, and are
losing money.</p>

<ul>
 <li>BTC Nuggets</li>
 <li>F2Pool</li>
</ul>

<p><b>Good pools:</b> these pools properly validate blocks.  Please
switch to them, at least until the bad pools have fixed their
systems.</p>

<ul>
  <li><a href="https://www.antpool.com/">AntPool</a></li>
  <li><a href="http://eligius.st/">Eligus</a></li>
  <li><a href="https://www.kano.is">kano/ckpool</a></li>
  <li><a href="http://p2pool.in/">P2Pool</a></li>
</ul>

<p><b>More information to follow.</b></p>

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