---
id: "CVE-2026-117603"
kind: "vulnerability"
aliases: ["CVE-2026-117603"]
title: "Electrum: Nostr Wallet Connect plugin lets clients exceed spending limits"
severity: "critical"
cvss: 9.3
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["bitcoin-wallet", "electrum", "nostr", "nwc", "package"]
not_affected_if: ["no-nwc-clients", "plugin-disabled"]
published_at: "2026-10-27T14:16:40+00:00"
first_seen_at: "2026-10-27T14:32:21+00:00"
updated_at: "2026-10-27T14:32:43+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-117603", "first_seen_at": "2026-10-27T14:32:21+00:00"}]
---

# Electrum: Nostr Wallet Connect plugin lets clients exceed spending limits

Electrum before 4.7.2 has a Nostr Wallet Connect plugin where concurrent pay_invoice requests race past the daily spending check, and millisatoshi amounts are truncated, letting a malicious NWC client drain more than the configured daily_limit_sat. The sources describe this as a loss of funds beyond the set limit.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Run `electrum version` and confirm whether it is below `4.7.2`.
- Check whether the Nostr Wallet Connect plugin is enabled and whether any NWC client is paired with the wallet.
- Look for a `daily_limit_sat` setting in the NWC plugin configuration.

## Fix

- Upgrade Electrum to `4.7.2` or later.
- Until upgraded, disable the Nostr Wallet Connect plugin or revoke NWC client connections.

## Timeline

- 2026-10-27T14:32:21+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-117603

## From the sources

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. Attackers can send concurrent pay_invoice requests that pass budget_allows_spend() before add_to_budget() runs, or repeatedly pay msat amounts that are floored to whole satoshis, to drain funds beyond the limit.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_