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.
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Tue, 27 Oct 2026 13:45:00 +0000

Type Values Removed Values Added
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.
Title Electrum before 4.8.3 Missing Signature Verification of Mempool Transactions
First Time appeared Electrum
Electrum electrum
Weaknesses CWE-347
CPEs cpe:2.3:a:electrum:electrum:*:*:*:*:*:*:*:*
Vendors & Products Electrum
Electrum electrum
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 9.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}


Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-27T13:09:51.347Z

Reserved: 2026-10-27T13:04:09.905Z

Link: CVE-2026-117601

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-27T14:16:39.947

Modified: 2026-10-27T16:03:45.247

Link: CVE-2026-117601

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-27T16:15:04Z

Weaknesses