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CVE-2026-117603— Electrum before 4.7.2 Nostr Wallet Connect Plugin Daily Spending Limit Bypass

Quick assessment

Affected
spesmilo electrum
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Electrum 4.7.2 之前的版本在 Nostr Wallet Connect（NWC）插件中存在一个绕过支出限制的安全漏洞。该漏洞允许恶意的 NWC 客户端利用非原子预算检查机制以及毫萨托希（millisatoshi）截断问题，突破 （每日限额）的限制。攻击者可以通过并发发送多个 请求，在 执行前使这些请求通过 的预算检查；或者反复支付被向下取整为整萨托希的毫萨托希金额，从而在超出预设限额的情况下耗尽资金。

CVSS 4.3 · Medium

Affected Version Matrix 2

VendorProduct Version RangeStatus
spesmilo electrum < 4.7.2 affected
4.7.2 unaffected
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I. Basic Information for CVE-2026-117603

Vulnerability Information
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Vulnerability Title
Electrum before 4.7.2 Nostr Wallet Connect Plugin Daily Spending Limit Bypass
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
检查时间与使用时间(TOCTOU)的竞争条件
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
spesmilo electrum 0 ~ 4.7.2 -

II. Public POCs for CVE-2026-117603

# POC Description Source Link Shenlong Link
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III. Intelligence Information for CVE-2026-117603

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Patches & Fixes for CVE-2026-117603 (1)

Vendor Advisories for CVE-2026-117603 (2)

Same Patch Batch · spesmilo · 2026-10-27 · 3 CVEs total

CVE-2026-117602 8.4 HIGH Electrum before 4.7.2 External Plugin Authorization Bypass Local Code Execution
CVE-2026-117601 7.5 HIGH Electrum before 4.8.3 Missing Signature Verification of Mempool Transactions

IV. Related Vulnerabilities

Same product: electrum
Same vendor: spesmilo
Same weakness: CWE-367