Quick answers
- Is CVE-2026-117603 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-117603 being exploited in the wild.
- How severe is CVE-2026-117603?
- Medium severity, with a CVSS score of 4.3, published 27 October 2026.
- Which products and versions are affected?
- Electrum before 4.7.2.
- Is there a fix for CVE-2026-117603?
- Yes: fixed in 4.7.2. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-117603 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-117603?
- Check whether you run Electrum at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: 4.7.2
Technical details
The vulnerability exists in the Nostr Wallet Connect plugin's budget checking logic. Attackers can exploit two attack vectors: (1) sending concurrent pay_invoice requests that all pass the budget_allows_spend() check before any call to add_to_budget() executes, and (2) repeatedly paying millisatoshi amounts that round down to whole satoshis, allowing fractional spending to accumulate beyond the daily_limit_sat. The fix involves atomic msat-denominated budget accounting and pre-incrementing the budget before payment attempts.
Affected products
- Electrum Electrum before 4.7.2
Timeline
- 2026-10-27: disclosed