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Description

Plunk is an open-source email platform built on top of AWS SES. Prior to version 0.9.0, the /webhooks/sns endpoint accepts Amazon SNS notification payloads from unauthenticated requests without verifying the SNS signature, certificate, or topic ARN, meaning anyone can forge a valid-looking webhook request. This allows an unauthenticated attacker to spoof SNS events to trigger workflow automations, unsubscribe contacts, manipulate email delivery metrics, and potentially exhaust billing credits. This issue has been patched in version 0.9.0.

PUBLISHED Reserved 2026-04-25 | Published 2026-05-08 | Updated 2026-05-08 | Assigner GitHub_M




CRITICAL: 9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Problem types

CWE-347: Improper Verification of Cryptographic Signature

Product status

< 0.9.0
affected

References

github.com/.../plunk/security/advisories/GHSA-9792-w86v-gx53

github.com/useplunk/plunk/releases/tag/v0.9.0

cve.org (CVE-2026-42193)

nvd.nist.gov (CVE-2026-42193)

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