CVE-2026-78006criticalobserved exploitationCWE-502

CVE-2026-78006: critical vulnerability in stellarwp The Events Calendar

The Events Calendar <= 6.17.4 - Unauthenticated PHP Object Injection to Remote Code Execution

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70Vexday Risk Score

Prioritize patching. It exploitation observed by VulnCheck and has a public proof of concept.

ssvc Actcvss 9.8epss 1.5%
from disclosure to weaponsame day
Published on NVDSep 12
1st PoCSep 12
VulnCheckSep 12
The The Events Calendar plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 6.17.4 via the is_safe_widget_instance function. This is due to insufficient protection in is_safe_widget_instance, which can be bypassed because PHP fires magic methods during its pre-parse, combined with enable_rendering_widget_copied() forging a valid wp_hash integrity attribute before unserialize() is reached. This makes it possible for unauthenticated attackers to execute code on the server. This is exploitable without authentication or approval because the plugin's V2 single-event template runs do_blocks() over buffered comment HTML, and WordPress returns a moderation-hash URL that allows an unauthenticated commenter to immediately view their own pending comment, delivering the injected block markup to the vulnerable code path before any moderation occurs. This does require comments to be enabled and visible on events.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products
stellarwp · The Events Calendar
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