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TI-2026-30514 Aliases CVE-2026-42193

Plunk: SNS webhook forgery

Priority MEDIUM 46CWE-347Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
None · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-347.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00127 2nd percentileScored 2026-11-07
Fix Fixed plunk (useplunk): 0.9.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
useplunkplunkbefore 0.9.00.9.0Patch availableCNA
  • plunk Vendoruseplunk Affected before 0.9.0 Fixed in 0.9.0 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:useplunk:plunk:*:*:*:*:*:*:*:*——useplunk
  • cpe:2.3:a:useplunk:plunk:*:*:*:*:*:*:*:* Versions — — ·useplunk

Remediation

  • Fix · CNA plunk (useplunk) Fixed in 0.9.0

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-42193

References

Other 2

  • TI-2026-24634 Plunk has SSRF via unvalidated AWS SNS SubscriptionConfirmation in POST /webhooks/sns CVSS 3.1CRITICAL 9.3
  • TI-2026-27197 Plunk has a CRLF Email Header Injection in raw MIME message construction allows… CVSS 3.1HIGH 8.5
  • TI-2026-30513 Plunk: Stored XSS in campaign view CVSS 3.1MEDIUM 5.4
  • TI-2026-24633 Plunk has Stored Cross-Site Scripting (XSS) via SVG File Upload CVSS 3.1MEDIUM 5.4

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences