# Electrum Bitcoin wallet security vulnerability

> Live situation record from CLSTR: https://clstr.news/situations/electrum-bitcoin-wallet-security-vulnerability
> Updated: 2026-10-25T08:25:12.000Z. Sources: 10. Developments: 2.

Developers of the Electrum Bitcoin wallet released version 4.8.3 to address a high-severity security flaw. The vulnerability allowed malicious servers to exploit the wallet’s client-server architecture by substituting legitimate, unconfirmed transactions with fraudulent ones.

In the reported exploit, a compromised server could intercept a user’s intended payment and present a fake transaction. These fraudulent transactions often used lookalike addresses where the final four characters matched the legitimate destination to avoid detection. The vulnerability became critical when users utilized the ‘Replace-By-Fee’ (RBF) feature to speed up a transaction; by approving a fee increase, users inadvertently signed the attacker’s fraudulent transaction instead. While the exact scale of the theft remains unconfirmed, developers reported that at least one user lost funds.

## Timeline

### 2026-10-25: Electrum wallet vulnerability and Bitget hack outflows reported

Electrum released a security patch for a Bitcoin wallet vulnerability exploited via fake transactions, while Arkham tracks $19.48 million in outflows linked to the Bitget hack.

2 sources. https://clstr.news/cluster/electrum-wallet-vulnerability-and-bitget-hack-outflows-reported

### 2026-10-25: Electrum releases security patch for Bitcoin wallet flaw

Electrum has patched a high-severity flaw in its Bitcoin wallet that allowed malicious servers to trick users into signing fraudulent transactions while attempting to increase transaction fees.

8 sources. https://clstr.news/cluster/electrum-releases-security-patch-for-bitcoin-wallet-vulnerability

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Cite as: Electrum Bitcoin wallet security vulnerability. CLSTR, https://clstr.news/situations/electrum-bitcoin-wallet-security-vulnerability