{"id":"CVE-2026-117601","state":"PUBLISHED","title":"Electrum before 4.8.3 Missing Signature Verification of Mempool Transactions","description":"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.","publishedAt":"2026-10-27T13:09:51.347Z","updatedAt":"2026-10-28T16:16:43.752Z","severity":{"score":9.3,"label":"Critical","version":"4.0","vector":"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","source":"VulnCheck"},"assigner":"VulnCheck","products":["spesmilo electrum"],"affected":[{"vendor":"spesmilo","product":"electrum","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"4.8.3","versionType":"semver"},{"version":"4.8.3","status":"unaffected","versionType":"semver"}]}],"references":["https://github.com/spesmilo/electrum/security/advisories/GHSA-6jp4-8v48-cc5v","https://github.com/spesmilo/electrum/commit/90fe30822561e515a9d2d6e5a352cc07780999eb","https://www.vulncheck.com/advisories/electrum-before-4.8.3-missing-signature-verification-of-mempool-transactions"],"weaknesses":["CWE-347"],"ingestedAt":"2026-10-29T20:10:52.580Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/117xxx/CVE-2026-117601.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-117601","state":"PUBLISHED","datePublished":"2026-10-27T13:09:51.347Z","dateUpdated":"2026-10-28T16:16:43.752Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-10-27T13:04:09.905Z"},"containers":{"cna":{"title":"Electrum before 4.8.3 Missing Signature Verification of Mempool Transactions","descriptions":[{"lang":"en","value":"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. 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