CVE-2026-15192Public exploitNetwork attack vector

Subscriber suppression via unsigned webhook events

Published Jul 9, 2026 · Updated Jul 9, 2026

Improper authentication in Mettle SendPortal 3.0.0 through 3.0.1 allows remote attackers to suppress campaign recipients via forged webhooks. The public APIv1 SendGrid, Postmark, Postal, and Mailjet handlers process provider event bodies without checking signatures or shared credentials. A valid message identifier is required; a forged bounce marks its subscriber unsubscribed and excludes that address from future campaigns.

CVSS severity6.5
Medium
EPSS probability0.76%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in Mettle SendPortal 3.0.0 through 3.0.1 allows remote attackers to suppress campaign recipients via forged webhooks. The public APIv1 SendGrid, Postmark, Postal, and Mailjet handlers process provider event bodies without checking signatures or shared credentials. A valid message identifier is required; a forged bounce marks its subscriber unsubscribed and excludes that address from future campaigns.

The record

CVE
CVE-2026-15192
Published
Jul 9, 2026
Updated
Jul 9, 2026
Vendor
Mettle
Product
SendPortal
Classifications
CWE-306, CWE-287, T1565.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3.0.0
  2. Affected versionversion=3.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mettle · SendPortalversion=3.0.0; version=3.0.1

Published CVSS scores

6.9TenableCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
6.5TenableCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
6.4TenableAV:N/AC:L/Au:N/C:N/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-306Missing Authentication for Critical Function
CWE-287Improper Authentication
T1565.001Stored Data Manipulation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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