Electrum: keys, security, fees and reviews

Software wallet

Status update

Security advisory (24 Oct 2026): Electrum disclosed a high-severity flaw (GHSA-6jp4-8v48-cc5v) on 24 October 2026: a malicious main server could swallow a just-broadcast transaction and show a conflicting one paying the attacker; fee-bumping it paid the attacker. Electrum says “some servers are performing this attack in the wild” and that one of two reporting users lost money; it states no amount. source ↗
Fix: Electrum says the flaw is fixed in version 4.8.3 and that users connected to servers they trust were not affected. source ↗

As of 1 November 2026, from the company’s own announcements unless stated otherwise.

In short

Key control: Self-custodial: private keys are encrypted and stay on the user's computer.
Fees: Wallet: Free software under the MIT licence; Bitcoin network fees apply, set with dynamic fee estimates.
Risks and caveats: Losing both the password and the seed means the funds cannot be recovered.
Checked: 1 November 2026

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Key facts

Wallet type: Software wallet
Developer: Electrum Technologies GmbH
Platforms: desktop
Open source: yes
Official site: electrum.org

Key facts checked on 1 November 2026 against official sources.

What is Electrum

Electrum is a free, open-source, Bitcoin-only software wallet created by Thomas Voegtlin in November 2011 and distributed by Electrum Technologies GmbH of Berlin. It is a light (SPV) wallet that uses Electrum servers and supports the Lightning Network, multisig, cold storage and hardware wallets.

Who holds the keys

Who holds the keys — Electrum
Parameter	Details
Key control	Self-custodial: private keys are encrypted and stay on the user's computer.
Seed phrase	Electrum's own seed phrase (132 bits of entropy) restores the whole wallet.
Recovery	A forgotten password cannot be recovered but the wallet can be restored from the seed; losing both means the money is lost.
Custodian	None; the developer stores no user account data and cannot freeze funds or undo transactions.

Features and supported networks

Features and supported networks — Electrum
Parameter	Details
Platforms	Linux (AppImage, x86_64), Windows 10 (1809) and higher, macOS 11 and higher, Android 8.0 and higher (Google Play, F-Droid, APK), and Python sources.
Supported networks	Bitcoin only, with the Lightning Network.
Connectivity	Connects to about 10 Electrum servers; confirmed transactions are verified with SPV, and the main server is trusted for unconfirmed ones.
Multisig	Multisignature wallets split spending permission between several wallets.
Hardware wallet support	Third-party plugins for multisig services and hardware wallets.
Cold storage	Keys can be kept offline with a watching-only wallet online.

Security and audits

Open source under the MIT licence; code on GitHub (spesmilo/electrum).
Release binaries are reproducible and signed by several builders; website changes must be signed by both ThomasV and SomberNight.
Security fixes are published as GitHub advisories; 4.8.3 (23 October 2026) fixed a high-severity issue that Electrum says malicious servers were exploiting in the wild.
Electrum offers no private support; people posing as 'Electrum support' in private channels are most likely imposters.

Security incidents

Security incidents — Electrum
Date	What happened	Source
26 December 2018	Phishing: Electrum developer SomberNight reported an ongoing attack in which attacker-run Electrum servers returned error messages to clients broadcasting a transaction, urging users to download malware disguised as an Electrum update. The attacker ran many servers to raise the chance of connection. Version 3.3.3 (25 January 2019) stopped showing server error messages to users. Funds returned: Electrum states no amount and no recovery.	github.com
7 April 2019	Outage: Electrum said its servers were under a DoS attack, that it was working on a more robust server version, and that affected users should disable auto-connect and select a server manually.	x.com
24 October 2026	Exploit: Electrum disclosed a high-severity flaw (GHSA-6jp4-8v48-cc5v): a malicious main server could swallow a just-broadcast transaction and show a conflicting one paying the attacker; fee-bumping it paid the attacker. Electrum says some servers were doing this in the wild and one of two reporting users lost money. Fixed in 4.8.3; users connected to servers they trust were not affected. Funds returned: Electrum states no amount.	github.com

Further incidents are reported by third parties (press, incident databases) but are not confirmed in the company’s own channels, so they are not listed here.

Fees

Fees — Electrum
Parameter	Details
Wallet	Free software under the MIT licence; Bitcoin network fees apply, set with dynamic fee estimates.

History

History — Electrum
Date	Event
November 2011	Electrum was created by Thomas Voegtlin.
2013	Electrum Technologies GmbH was founded by Thomas Voegtlin.
26 December 2018	Electrum disclosed a phishing attack via malicious servers.
25 January 2019	Version 3.3.3 stopped exposing users to server error messages.
7 April 2019	Electrum reported a DoS attack on its servers.
3 July 2020	Version 4.0.1 was released (experimental Lightning support).
23 October 2026	Version 4.8.3 was released as a security update.

Risks and caveats

Losing both the password and the seed means the funds cannot be recovered.
The main server is trusted for unconfirmed transactions and can link the wallet's addresses; malicious servers exploited this until 4.8.3.
Electrum should only be downloaded from electrum.org.
People posing as 'Electrum support' in private channels are most likely imposters.

About the developer

Legal entity: Electrum Technologies GmbH, registered as HRB 164636; entity created on 3 February 2015; legal address Paul-Lincke-Ufer 8 D, 10999 Berlin, Germany (GLEIF LEI record, status active)
Developer: Electrum Technologies GmbH and open-source contributors; Thomas Voegtlin and SomberNight have GitHub write access.
Founders: Thomas Voegtlin.
Headquarters: Paul-Lincke-Ufer 8d, 10999 Berlin, Germany.

Official links

Website: electrum.org
Docs: electrum.readthedocs.io/en/latest/faq.html
Source code: github.com/spesmilo/electrum
Security: github.com/spesmilo/electrum/security/advisories
Download: f-droid.org/en/packages/org.electrum.electrum
Download: play.google.com/store/apps/details?id=org.electrum.electrum&hl=en

Questions and answers

Is Electrum wallet safe?

Keys are encrypted on the user's device and builds are reproducible and multi-signed. Electrum fixed a server-side attack in 4.8.3 (October 2026) that it says was used in the wild, so users should run 4.8.3 or later.

Is Electrum self-custodial?

Yes. Private keys never leave the user's computer, and the developer cannot freeze funds or undo transactions.

Is Electrum open source?

Yes. It is released under the MIT licence with code on GitHub (spesmilo/electrum).

Does Electrum charge fees?

The software is free; users pay Bitcoin network fees, which Electrum estimates dynamically.

Who makes Electrum?

Thomas Voegtlin created it in November 2011; Electrum Technologies GmbH of Berlin, founded in 2013, distributes it with open-source contributors.

Sources

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Page updated: 2026-11-06