Quick answers
- Is CVE-2026-104084 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-104084 being exploited in the wild.
- How severe is CVE-2026-104084?
- High severity, with a CVSS score of 8.8, published 9 October 2026.
- Which products and versions are affected?
- SmarterTools SmarterMail before build 9777.
- Is there a fix for CVE-2026-104084?
- Yes: fixed in SmarterMail build 9777. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-104084 attacked?
- It is attacked over the network, in a hosted service.
- Am I affected by CVE-2026-104084?
- Check whether you run SmarterTools SmarterMail 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: SmarterMail build 9777
Technical details
The vulnerability exists in the JWT token refresh mechanism at POST /api/v1/auth/refresh-token, where role claims embedded in JWT tokens at issuance are never revalidated against the account's current role when the token is redeemed. An attacker who captures a refresh token issued before an administrator was demoted can replay it to obtain a new access token that retains the original higher privilege level until natural token expiry. This affects authentication and authorization enforcement for administrative accounts.
Affected products
- SmarterTools SmarterMail before build 9777
Timeline
- 2026-10-09: disclosed
- 2026-10-08: patched: Build 9777 released