Forgeable JWT Vulnerability in BillionMail by aaPanel
CVE-2026-111367

6.9MEDIUM

Key Information:

Vendor

Aapanel

Status
Billionmail
Vendor
CVE Published:
15 October 2026

What is CVE-2026-111367?

BillionMail versions up to 4.9 contain a vulnerability due to a hard-coded cryptographic key. This flaw allows unauthenticated attackers to forge JSON Web Tokens (JWTs) used for subscription management. By exploiting this vulnerability, attackers can generate and submit forged tokens to endpoints like /api/unsubscribe, /api/unsubscribe_new, and /api/subscribe/confirm, enabling them to deactivate any user’s subscriptions or manipulate confirmed subscription statuses. This poses a significant risk to the integrity of user data and the reliability of subscription management in the application.

Affected Version(s)

BillionMail 0 <= 4.9

References

https://hackmd.io/@hieuPenguinnn/billionmail-unsubscribe-...
third-party-advisory
https://github.com/aaPanel/BillionMail/blob/v4.9/core/int...
technical-description
https://github.com/aaPanel/BillionMail/blob/v4.9/core/man...
technical-description

CVSS V4

Score:
6.9
Severity:
MEDIUM
Confidentiality:
None
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

hieuPenguinnn
.