Electrum Patches a Wallet Flaw in Version 4.8.3: Update Now if You Use It

By Kevin · 2026-10-26 · News

Oct. 26 (CandyPulse) — If you use the Electrum Bitcoin wallet, now is a good time to update. Electrum released version 4.8.3 on Oct. 24, fixing a high-severity flaw that let a malicious server trick the wallet into sending a payment to an attacker when the user tried to speed it up.

Key takeaways

Electrum 4.8.3 fixes a flaw involving pending transactions and fee bumps
A malicious server could swap a user's payment for one going to an attacker's address
Electrum says the flaw was exploited in the wild; at least one user lost funds
Users on trusted or self-run servers were not affected
Update now, and download only from electrum.org

How the attack worked

Electrum connects to outside servers to see the blockchain. Here's how a bad server could abuse that:

You send a Bitcoin payment, but it's slow to confirm
A malicious server hides your real payment and shows a fake pending transaction to the attacker's address instead
Older Electrum versions didn't check the signatures on that fake transaction
You click "increase fee" (Replace-By-Fee) to speed things up
The wallet signs the attacker's version, sending your coins to them

The fix

Detail	Answer
Fixed version	Electrum 4.8.3
Released	Oct. 24, 2026
What changed	The wallet now verifies signatures on unconfirmed transactions that spend your coins and rejects invalid ones
Who was at risk	Users connected to untrusted public servers who used fee bumping
Who was safe	Users on trusted or self-run servers

What you should do

Update to 4.8.3 right away
Download only from electrum.org, and verify the signatures
Before you sign any transaction, especially a fee bump, double-check the address and amount
If you can, connect to a server you trust or run your own

Why it matters

Electrum is one of the oldest and most widely used Bitcoin wallets. Bugs like this are rare, but they show why wallet updates matter. Related security stories: the XRP Ledger overflow bug, patched and disclosed, Ledger's hardware implant warning and what strangers can learn from your public wallet.

What's next

Watch for Electrum's full advisory and any further reports of losses. More on our Bitcoin topic page.

Disclaimer: This article is for information only and is not financial or security advice. Always download wallet software from official sources and verify it before use.