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CVE-2026-117601— Electrum before 4.8.3 Missing Signature Verification of Mempool Transactions

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 4.8.3 之前的版本无法验证未确认内存池（mempool）交易中由钱包拥有的输入签名。这一缺陷使得恶意服务器能够将用户刚刚广播的交易替换为与之冲突的交易。攻击者可以吞掉用户的原始交易，并展示一个无效的、零手续费的伪造交易，该交易将资金支付给攻击者地址，从而诱骗用户通过替代费用广播（RBF）机制提高手续费并签署该伪造交易。

CVSS 7.5 · High Updated Oct 27, 2026

Possible ATT&CK Techniques 2 AI

T1059 · Command and Scripting Interpreter T1566 · Phishing

Affected Version Matrix 2

Vendor	Product	Version Range	Status
spesmilo	electrum	`< 4.8.3`	affected
		`4.8.3`	unaffected

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Vulnerability Information

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Vulnerability Title

Electrum before 4.8.3 Missing Signature Verification of Mempool Transactions

Source: CVE Program / CVE List V5

Vulnerability Description

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.

Source: CVE Program / CVE List V5

CVSS Information

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Source: CVE Program / CVE List V5

Vulnerability Type

密码学签名的验证不恰当

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
spesmilo	electrum	0 ~ 4.8.3	-

II. Public POCs for CVE-2026-117601

#	POC Description	Source Link	Shenlong Link

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No public POC found.

III. Intelligence Information for CVE-2026-117601

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Vendor Advisories for CVE-2026-117601 (2)

https://www.cve.org/CVERecord?id=CVE-2026-117601

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-2026-117603	4.3 MEDIUM	Electrum before 4.7.2 Nostr Wallet Connect Plugin Daily Spending Limit Bypass

IV. Related Vulnerabilities

Same product: electrum

Same vendor: spesmilo

Same weakness: CWE-347