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.
Published: 2026-10-27
Score: 9.3 Critical
EPSS: n/a
KEV: No
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

No solution or workaround provided in the CVE record.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

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'}

Subscriptions

Electrum Electrum
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 : Received

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

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

Link: CVE-2026-117601

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-347

    Improper Verification of Cryptographic Signature