CVE-2026-117601 Electrum - Authentication Bypass

Electrum < 4.8.3 contains a transaction signature verification flaw caused by failure to verify wallet-owned inputs in unconfirmed mempool transactions, letting malicious servers replace broadcast transactions, exploit requires malicious server interaction.

CVSS base score 7.5 /10
High
CISA KEV
Exploited in the wild
Public exploit
None known
EPSS
0.18% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Authentication Bypass
Impact
Data Tampering
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Published
27 October 2026
Updated
29 October 2026
Weakness
CWE-347

Vendor fix

Upgrade to version 4.8.3 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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