Vulnerability details
CVE-2026-117601
spesmilo electrum
Electrum before 4.8.3 Missing Signature Verification of Mempool Transactions
CVSS 4.0
9.3Critical
Official 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.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 9.3Critical | 4.0 | CVEProject cvelistV5 (CNA) (VulnCheck) | 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 |
| 7.5High | 3.1 | CVEProject cvelistV5 (CNA) (VulnCheck) | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| spesmilo | electrum | v < 4.8.3 | CVEProject cvelistV5 (CNA) |
References and advisories
3- https://github.com/spesmilo/electrum/security/advisories/GHSA-6jp4-8v48-cc5v vendor-advisory
- https://github.com/spesmilo/electrum/commit/90fe30822561e515a9d2d6e5a352cc07780999eb patch
- https://www.vulncheck.com/advisories/electrum-before-4.8.3-missing-signature-verification-of-mempool-transactions third-party-advisory
Kolun on Telegram @kolunsec
Exploited CVEs, key news and a daily digest
Alerts for this product's next CVEsFollow the product to get new vulnerabilities on Telegram.
Details
- Published
- 2026-10-27
- Last updated
- 2026-10-28
- State
- Published
- Assigner (CNA)
- VulnCheck
- Kolun priority
- 16 · Low
Exploit prediction (EPSS)
0.17%
Probability of exploitation in 30 days
7.1%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- Yes
- Exploitation
- None
- Technical impact
- Total
Weaknesses (CWE)
- CWE-347Improper Verification of Cryptographic Signature