CVE-2026-128334

MEDIUM 4.8

listmonk 6.2.0 before 7.0.0-beta.2 Missing Authentication via Azure Bounce Webhook

CVSS Score

4.8

EPSS Score

0.0%

EPSS Percentile

0th

listmonk 6.2.0 before 7.0.0-beta.2 contains a missing authentication vulnerability that allows unauthenticated attackers to submit Azure Event Grid bounce webhooks when no shared secret is configured. Attackers can POST forged EmailDeliveryReportReceived events with Bounced status to /webhooks/service/azure to blocklist, unsubscribe, or delete arbitrary subscribers.

CWE	CWE-636
Vendor	knadh
Product	listmonk
Published	Nov 13, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

Low

Affected Versions

knadh / listmonk

6.2.0 < 7.0.0-beta.2

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/knadh/listmonk/commit/0c155bd2663d9ec8053ac0d1ab63f021fbb5a0dc github.com: https://github.com/knadh/listmonk/releases/tag/v7.0.0-beta.2 github.com: https://github.com/knadh/listmonk/blob/v7.0.0-beta.1/internal/bounce/webhooks/azure.go#L141-L149 github.com: https://github.com/biofool/listmonk/issues/5 vulncheck.com: https://www.vulncheck.com/advisories/listmonk-6.2.0-before-7.0.0-beta.2-missing-authentication-via-azure-bounce-webhook

Credits

Komiljon Ayubov Kenneth Kron Kailash Nadh