Electrum vulnerabilities

Electrum before 4.7.2 contains a spending limit bypass vulnerability in the Nostr Wallet Connect plugin that allows malicious NWC clients to exceed daily_limit_sat by exploiting non-atomic budget checks and millisatoshi truncation.

Electrum 4.6.0 before 4.7.2 contains an authorization bypass in the external plugin loader, which executes a plugin's __init__.py module when the plugin is marked enabled in the config file without verifying its plugin-password signature. A rogue local process with write access to the Electrum data directory can place plugin code in the plugins/ folder and mark it enabled, causing arbitrary code execution inside the Electrum process.

Electrum before 4.8.3 fails to verify signatures of wallet-owned inputs in unconfirmed mempool transactions, allowing malicious servers to replace a just-broadcast transaction with a conflicting one. Attackers can swallow the user's transaction and display an invalid zero-fee copy paying an attacker address, tricking users into RBF fee-bumping and signing it.