Vulnerability · Published May 8, 2026 · Assigned by GitHub_M

CVE-2026-42193Plunk: SNS webhook forgery

Critical 9.1

In plain English

A critical-severity security flaw in plunk from useplunk. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities).

Severity (CVSS 3.1)9.1Critical

Exploit odds (30 days)0.1%top 97.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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 (as reported)

Vendor	Product	Versions
useplunk	plunk	< 0.9.0

Weakness: CWE-347 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

References

https://github.com/useplunk/plunk/security/advisories/GHSA-9792-w86v-gx53 x_refsource_CONFIRM
https://github.com/useplunk/plunk/releases/tag/v0.9.0 x_refsource_MISC