CVE-2026-117601criticalobserved exploitationCWE-347

CVE-2026-117601: critical vulnerability in spesmilo electrum

Electrum before 4.8.3 Missing Signature Verification of Mempool Transactions

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50Vexday Risk Score

Prioritize patching. It exploitation observed by VulnCheck.

ssvc Actcvss 9.3epss 0.2%
from disclosure to weapon
Published on NVDOct 27
VulnCheckOct 27
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.
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
Affected products
spesmilo · electrum
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