CVE-2026-128334

EUVD-2026-125043
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.
Failing Open
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
4.8 MEDIUM
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L
Awaiting analysis
This vulnerability is currently awaiting analysis.
Base Score
CVSS 3.x
EPSS Score
Percentile: 40.7%
Common Weakness Enumeration
References
https://github.com/biofool/listmonk/issues/5
https://github.com/knadh/listmonk/blob/v7.0.0-beta.1/internal/bounce/webhooks/azure.go#L141-L149
https://github.com/knadh/listmonk/commit/0c155bd2663d9ec8053ac0d1ab63f021fbb5a0dc
https://github.com/knadh/listmonk/releases/tag/v7.0.0-beta.2
https://www.vulncheck.com/advisories/listmonk-6.2.0-before-7.0.0-beta.2-missing-authentication-via-azure-bounce-webhook