CVE-2026-117601
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk7th percentile - higher than 7% of all known CVEs
Summary
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.
Risk Assessment
A user may be tricked into signing a transaction that pays the attacker, resulting in loss of funds. The risk affects users connecting to untrusted or malicious Electrum servers.
Recommendation
Update Electrum to 4.8.3 or later. Use only trusted Electrum servers and verify transaction details before signing.
Other vulnerabilities in Electrum
See all- CVE-2026-117603Medium
Electrum before 4.7.2 contains a spending limit bypass vulnerability in the Nostr Wallet Connect plugin that allows malicious NWC clients to exceed daily_limit_sat by exploiting non-atomic budget checks and millisatoshi truncation.
- CVE-2026-117602High
Electrum 4.6.0 before 4.7.2 contains an authorization bypass in the external plugin loader, which executes a plugin's __init__.py module when the plugin is marked enabled in the config file without verifying its plugin-password signature. A rogue local process with write access to the Electrum data directory can place plugin code in the plugins/ folder and mark it enabled, causing arbitrary code execution inside the Electrum process.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS