Electrum: Malicious server can replace a just-broadcast tx and try to trick user into RBF-ing it

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

• CISA KEV Not listed.
• EPSS 0.0018, the 7th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

1. 31 Oct 2026, 14:07 UTC First seen by agentprime
2. 31 Oct 2026, 14:07 UTC Confirmed by OSV

Sources

• GitHub Advisory Database: GHSA-6jp4-8v48-cc5v
• OSV: GHSA-6jp4-8v48-cc5v
• github.com/spesmilo/electrum/security/advisories/GHSA-6jp4-8v48-cc5v
• nvd.nist.gov/vuln/detail/CVE-2026-117601
• github.com/spesmilo/electrum/commit/90fe30822561e515a9d2d6e5a352cc07780999eb
• github.com/spesmilo/electrum
• www.binance.com/en/square/post/381361716824742
• www.vulncheck.com/advisories/electrum-before-4.8.3-missing-signature-verification-of-mempool-transactions

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.