Bitcoin Core 30.0 and 30.1 have a coin loss risk, and the official versions have been withdrawn.

The Bitcoin Core project recently issued a security warning regarding wallet migration vulnerabilities present in versions 30.0 and 30.1. In very rare cases, users migrating from older wallets may face the risk of fund loss. The official versions have been withdrawn, and a fix is expected to be released in version 30.2.

What exactly is this bug?

According to the latest information, versions 30.0 and 30.1 of Bitcoin Core contain serious flaws when handling migration of old BDB wallets. When users attempt to migrate a long-unupdated BDB wallet to a custom directory and enable pruning, the system may erroneously delete all wallet files under the entire wallet directory.

It’s important to clarify: affected are BDB wallets, which are based on the database format used in early versions of Bitcoin Core. Modern Bitcoin Core wallets have switched to SQLite, so most current users are not impacted.

How many users are truly affected?

The official statement emphasizes that this bug is triggered only in “very rare circumstances,” including:

• Using very old BDB-format wallets (not upgraded for years)
• Wallets that have never been renamed or upgraded
• Attempting to migrate to a custom wallet directory
• While pruning is enabled

In other words, users employing hardware wallets, modern wallet software, or those who have upgraded Bitcoin Core in recent years generally do not need to worry. The bug mainly threatens long-neglected, locally stored very old wallets.

What is the official response?

According to relevant information, Bitcoin Core developers have taken the following measures:

• Version 30.1, released on January 1st, has been withdrawn
• Version 30.2 will include the fix
• Before version 30.2 is released, users are advised not to migrate old wallets using versions 30.0 or 30.1

Note that this bug only affects the wallet migration process. All other functions, including running nodes and using existing wallets, are unaffected.

What should users do now?

The most important advice: if you have a very old BDB wallet that hasn’t been updated in a long time, make sure to back it up before upgrading to 30.2. This not only safeguards against this bug but is also a fundamental principle for protecting any wallet.

What does this reflect?

Interestingly, the timing of this bug is quite peculiar. According to recent reports, Bitcoin Core saw a significant rebound in development activity in 2025, with 135 independent contributors submitting approximately 285,000 lines of code, and mailing list traffic increasing by 60% year-over-year. This marks the first uptick since 2018.

Additionally, Bitcoin Core v30 completed its first-ever third-party security audit, which concluded that the codebase is “mature and thoroughly tested,” with no serious or high-risk vulnerabilities found.

What does this imply? Increased development activity and successful security audits are positive signals, but the emergence of this wallet migration bug also reminds us that even the most active projects require cautious user practices. Upgrading versions is not always necessary, especially if your wallet is functioning well.

Summary

The wallet migration bug in Bitcoin Core versions 30.0 and 30.1 is a serious security issue, but its impact is limited, mainly threatening long-neglected, unmaintained BDB wallets. The official team has promptly withdrawn these versions and promised to fix the issue in 30.2. For most users, continuing to run nodes and wallets on existing versions is safe—just avoid migrating old wallets until the fix is available. This incident reminds us that even the most active development projects require cautious user behavior—timely backups, careful upgrades, and staying informed through official channels are fundamental to asset security.