CVE-2026-16267Public exploitNetwork attack vector

Unauthenticated PHP object injection via date field

Published Aug 8, 2026 · Updated Aug 8, 2026

PHP object injection in Tribulant Software Newsletters before 4.16 allows remote attackers to instantiate PHP objects through public date fields. Public subscription-form date values reach maybe_unserialize() without an allowed_classes restriction, so supplied classes are instantiated and __wakeup executes. A public subscription form with a Date field and a usable gadget class are required; a resulting POP chain can execute code in WordPress.

CVSS severity8.1
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

PHP object injection in Tribulant Software Newsletters before 4.16 allows remote attackers to instantiate PHP objects through public date fields. Public subscription-form date values reach maybe_unserialize() without an allowed_classes restriction, so supplied classes are instantiated and __wakeup executes. A public subscription form with a Date field and a usable gadget class are required; a resulting POP chain can execute code in WordPress.

The record

CVE
CVE-2026-16267
Published
Aug 8, 2026
Updated
Aug 8, 2026
Vendor
Tribulant Software
Product
Newsletters
Classifications
CWE-502, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 8, 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=0 <4.16

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Tribulant Software · Newslettersversion=0 <4.16

Published CVSS scores

7.6TenableAV:N/AC:H/Au:N/C:C/I:C/A:C
8.1TenableCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

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.

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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-502Deserialization of Untrusted Data
T1190Exploit Public-Facing Application

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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