CVE-2026-117603

Medium

Description

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.

SeverityMedium

CVSS4.3

Exploit probability—

ProductSpesmilo Electrum

PublishedOct 27, 2026

First seenOct 27, 2026

Weakness typeCWE-367CWE-367

How to fix

Update

spesmilo electrum4.7.2 or later

Patches

Vendor advisories

github.com/spesmilo/electrum/security/advisories/GHSA-q7m2-785w-r585

Affected products

Product	Affected versions	Fixed in
spesmilo electrum	v < 4.7.2	4.7.2

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