by Kastro
Paper/Archive/CVE-2026-42193

CVE-2026-42193

useplunk plunk — Plunk: SNS webhook forgery

EPSS 0.1%CVSS 9.1
critical.is priorityof 100
28
CVSS 9.1 (CNA)9.1 / 10 × 3027.3Not in CISA KEV+300.0EPSS percentile 2.4.024 × 200.5No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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

ProductAffectedFixed inSource
plunk< 0.9.0–CNA

Scores by source

GitHub_M (CNA)9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

refgithub.com/useplunk/plunk/security/advisories/GHSA-9792-w86v-gx53refgithub.com/useplunk/plunk/releases/tag/v0.9.0