CVE-2026-117601
Electrum before 4.8.3 Missing Signature Verification of Mempool Transactions
- State
- Published
- Severity
- 9.3 Critical
- Published
- Oct 27, 2026
- Updated
- Oct 28, 2026
- Reserved
- Oct 27, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 9.3 Critical | 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 | VulnCheck |
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H | VulnCheck |
Weaknesses
- CWE-347 Improper Verification of Cryptographic Signature
Affected Products
| Product | Versions |
|---|---|
electrumspesmilo |
|
References
- GitHub Security Advisory (GHSA-6jp4-8v48-cc5v)vendor-advisory
- Patch Commitpatch
- VulnCheck Advisory: Electrum before 4.8.3 Missing Signature Verification of Mempool Transactionsthird-party-advisory
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