CVE-2026-78265Network attack vector

Unauthenticated object injection via copied widget deserialization

Published Aug 24, 2026 · Updated Aug 25, 2026

PHP object injection in Nexcess The Events Calendar 6.17.2 and earlier allows remote attackers to instantiate objects through REST requests. Copied legacy widget handling base64-decodes an encoded instance and processes the serialized bytes without rejecting embedded objects. No authentication or user interaction is required; impact depends on an available POP chain and can include code execution, SQL injection, path traversal, or service interruption.

CVSS severity9.8
Critical
EPSS probability0.31%
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 Nexcess The Events Calendar 6.17.2 and earlier allows remote attackers to instantiate objects through REST requests. Copied legacy widget handling base64-decodes an encoded instance and processes the serialized bytes without rejecting embedded objects. No authentication or user interaction is required; impact depends on an available POP chain and can include code execution, SQL injection, path traversal, or service interruption.

The record

CVE
CVE-2026-78265
Published
Aug 24, 2026
Updated
Aug 25, 2026
Vendor
The Events Calendar
Product
The Events Calendar
Classifications
CWE-502, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 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=n/a <=6.17.2 changes=[{"at":"6.17.3","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Events Calendar · The Events Calendarversion=n/a <=6.17.2 changes=[{"at":"6.17.3","status":"unaffected"}]

Published CVSS scores

9.8PatchstackCVSS:3.1/AV:N/AC:L/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.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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