CVE-2026-104084
SmarterMail < Build 9777 Stale JWT Role Claim Privilege Escalation via Refresh Token
- State
- Published
- Severity
- 8.7 High
- Published
- Oct 9, 2026
- Updated
- Oct 27, 2026
- Reserved
- Oct 1, 2026
Description
SmarterMail before build 9777 contains a privilege escalation vulnerability where JWT access and refresh tokens embed a role claim at issuance that is not revalidated against the account's current role when redeemed through POST /api/v1/auth/refresh-token. Attackers who capture a refresh token issued before an administrator demotion, or a demoted user whose session was not actively polling at the time of demotion, can replay the stale token to obtain a new access token retaining the higher-privilege role (such as DomainAdmin or SysAdmin) until natural token expiry.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.7 High | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 8.8 High | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | VulnCheck |
Weaknesses
- CWE-613 Insufficient Session Expiration
Affected Products
| Product | Versions |
|---|---|
SmartermailSmartertools |
|
References
- Release Notesrelease-notespatch
- Researcher Blogtechnical-descriptionexploit
- VulnCheck Advisory: SmarterMail < Build 9777 Stale JWT Role Claim Privilege Escalation via Refresh Tokenthird-party-advisory
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