What is CVE-2026-42193?

CVE-2026-42193 is a critical-severity vulnerability in Useplunk Plunk, classified under Improper Verification of Cryptographic Signature. CVSS score: 9.1/10. Published 2026-05-08.

How severe is CVE-2026-42193?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Vulnerability in Useplunk Plunk

CVE-2026-42193

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…

EPSS: 0.000 (5.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H.

Affected products

Useplunk Plunk — versions < 0.9.0

Weakness classification (CWE)

CWE-347 — Improper Verification of Cryptographic Signature

References

security-advisories@github.com (x_refsource_CONFIRM)
security-advisories@github.com (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-42193?: CVE-2026-42193 is a critical-severity vulnerability in Useplunk Plunk, classified under Improper Verification of Cryptographic Signature. CVSS score: 9.1/10. Published 2026-05-08.
How severe is CVE-2026-42193?: Critical severity. CVSS v3 base score is 9.1 out of 10.