{
  "version": "https://jsonfeed.org/version/1.1",
  "title": "Electrum wallet: malicious servers swap just-sent transactions and trick users into fee-bumping a payment to the attacker · updates",
  "home_page_url": "https://pwn.watch/i/electrum-malicious-server-rbf-fee-bump-theft",
  "feed_url": "https://pwn.watch/i/electrum-malicious-server-rbf-fee-bump-theft/feed.json",
  "description": "Electrum before 4.8.3 trusted its server for unconfirmed transactions without checking their signatures. A malicious Electrum server can swallow a transaction the user just broadcast and show a conflicting fake (with invalid signatures) that pays an attacker address ground to match the last four characters of the real one. If the user then bumps the fee with Replace-By-Fee, the wallet signs a valid payment to the attacker. Electrum says some servers are doing this in the wild, and one user lost money. Upgrade to Electrum 4.8.3; until then, check every output address and amount before signing, including fee bumps. Users connecting only to a server they run or trust are not affected.",
  "language": "en",
  "_pwn": {
    "slug": "electrum-malicious-server-rbf-fee-bump-theft",
    "severity": "high",
    "status": "live",
    "patchStatus": "patched",
    "rss": "https://pwn.watch/i/electrum-malicious-server-rbf-fee-bump-theft/feed.xml",
    "llms": "https://pwn.watch/i/electrum-malicious-server-rbf-fee-bump-theft/llms.txt",
    "json": "https://pwn.watch/i/electrum-malicious-server-rbf-fee-bump-theft.json"
  },
  "items": [
    {
      "id": "https://pwn.watch/i/electrum-malicious-server-rbf-fee-bump-theft#2026-10-24-066138a8",
      "url": "https://pwn.watch/i/electrum-malicious-server-rbf-fee-bump-theft#2026-10-24-066138a8",
      "title": "Electrum wallet: malicious servers swap just-sent transactions and trick users into fee-bumping a payment to the attacker: Electrum 4.8.3 binaries released and GHSA-6jp4-8v48-cc5v published; the client now verifies signatures of its own inputs in mempool transactions.",
      "content_text": "Electrum wallet: malicious servers swap just-sent transactions and trick users into fee-bumping a payment to the attacker: Electrum 4.8.3 binaries released and GHSA-6jp4-8v48-cc5v published; the client now verifies signatures of its own inputs in mempool transactions.\n\nSource: https://github.com/spesmilo/electrum/security/advisories/GHSA-6jp4-8v48-cc5v",
      "date_published": "2026-10-24T00:00:00.000Z",
      "external_url": "https://github.com/spesmilo/electrum/security/advisories/GHSA-6jp4-8v48-cc5v",
      "tags": [
        "high"
      ]
    },
    {
      "id": "https://pwn.watch/i/electrum-malicious-server-rbf-fee-bump-theft#2026-10-18-794de252",
      "url": "https://pwn.watch/i/electrum-malicious-server-rbf-fee-bump-theft#2026-10-18-794de252",
      "title": "Electrum wallet: malicious servers swap just-sent transactions and trick users into fee-bumping a payment to the attacker: Second private report: a user loses funds after fee-bumping the substituted transaction.",
      "content_text": "Electrum wallet: malicious servers swap just-sent transactions and trick users into fee-bumping a payment to the attacker: Second private report: a user loses funds after fee-bumping the substituted transaction.\n\nSource: https://github.com/spesmilo/electrum/security/advisories/GHSA-6jp4-8v48-cc5v",
      "date_published": "2026-10-18T00:00:00.000Z",
      "external_url": "https://github.com/spesmilo/electrum/security/advisories/GHSA-6jp4-8v48-cc5v",
      "tags": [
        "high"
      ]
    },
    {
      "id": "https://pwn.watch/i/electrum-malicious-server-rbf-fee-bump-theft#2026-10-11-3a5105fc",
      "url": "https://pwn.watch/i/electrum-malicious-server-rbf-fee-bump-theft#2026-10-11-3a5105fc",
      "title": "Electrum wallet: malicious servers swap just-sent transactions and trick users into fee-bumping a payment to the attacker: First private report: a user sees a different transaction in their wallet history after broadcasting.",
      "content_text": "Electrum wallet: malicious servers swap just-sent transactions and trick users into fee-bumping a payment to the attacker: First private report: a user sees a different transaction in their wallet history after broadcasting.\n\nSource: https://github.com/spesmilo/electrum/security/advisories/GHSA-6jp4-8v48-cc5v",
      "date_published": "2026-10-11T00:00:00.000Z",
      "external_url": "https://github.com/spesmilo/electrum/security/advisories/GHSA-6jp4-8v48-cc5v",
      "tags": [
        "high"
      ]
    }
  ]
}