Electrum 4.8.3 fixes a security vulnerability that could induce users to sign fraudulent transactions

According to Bitcoin News monitoring, Electrum released version 4.8.3 on October 24, 2026, fixing a security vulnerability that had been used in real attacks.

Malicious servers can present users with forged transactions and induce them to sign transactions that pay the attacker's address when users attempt to accelerate transactions with a replacement fee (RBF); attackers do not need to obtain the user's private key. Electrum stated that it has received two related reports, one of which involved a user losing Bitcoin after increasing the transaction fee, and advised users to update to version 4.8.3.