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OpenAdvisories
Critical · 9.1 CVE-2026-42193 EUVD-2026-28832

Plunk: SNS webhook forgery

Published May 8, 2026 · Updated May 11, 2026 · Assigned by GitHub_M

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.

Affected products

VendorProductAffectedFixed
useplunk plunk < 0.9.0 —

References