CVE-2026-111367 aaPanel CVE debrief

Who should care

Defenders responsible for systems using BillionMail version 4.9 or earlier should assess exposure and prioritize verification and potential remediation. They should also verify system exposure, prioritize remediation, and assess potential impact. Additionally, defenders should review compensating controls for exposed systems while remediation is scheduled and verified.

Why it matters

CVE-2026-111367 is a medium-severity vulnerability in BillionMail that allows unauthenticated attackers to forge JWTs due to a hard-coded cryptographic key. Defenders should verify system exposure, prioritize remediation, and assess potential impact.

• Potential deactivation of contacts or forced confirmed subscriptions via forged JWTs.
• Verification of system exposure to this vulnerability is required.
• Remediation priority is elevated due to the potential for unauthorized access.
• Further verification of affected scope and impact is necessary.

Technical summary

The vulnerability exists due to a hard-coded cryptographic key in BillionMail through version 4.9. This allows unauthenticated attackers to forge unsubscribe and subscribe-confirm JWTs by computing the key from shipped configuration constants. The forged tokens can be submitted to specific API endpoints, potentially deactivating any contact or forcing confirmed subscriptions. Defenders should prioritize verifying the presence of this vulnerability in their systems, especially if using BillionMail version 4.9 or earlier.

Defensive priority

Defenders should prioritize verifying the presence of this vulnerability in their systems, especially if using BillionMail version 4.9 or earlier, and consider upgrading to a fixed version if available.

Recommended defensive actions

• Verify the presence of BillionMail version 4.9 or earlier in your systems.
• Consider upgrading to a fixed version if available.
• Monitor API endpoints /api/unsubscribe, /api/unsubscribe_new, and /api/subscribe/confirm for suspicious activity.
• Implement additional authentication and validation for JWTs.
• Review compensating controls for exposed systems while remediation is scheduled and verified.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Evidence notes

The CVE record and NVD detail page provide information about the vulnerability. However, the exact impact and affected scope require further verification from the supplied official sources. Defenders should verify system exposure, prioritize remediation, and assess potential impact. The vulnerability allows unauthenticated attackers to forge JWTs, which could lead to unauthorized access or modifications.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.