CVE-2026-78006: Insecure Deserialization (CVSS 9.8)

Description

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.

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CVSS v3.1 Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0078

Probability of exploitation

0.54%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-502 Deserialization of Untrusted Data

References

Other References

https://plugins.trac.wordpress.org/browser/the-events-calendar/tags/6.17.3/common/src/Tribe/Utils/Collection_Trait.php#L247 https://plugins.trac.wordpress.org/browser/the-events-calendar/tags/6.17.3/src/Tribe/Collections/Lazy_Post_Collection.php#L82 https://plugins.trac.wordpress.org/browser/the-events-calendar/tags/6.17.3/src/Tribe/Views/V2/Template_Bootstrap.php#L213 https://plugins.trac.wordpress.org/browser/the-events-calendar/tags/6.17.3/src/Tribe/Views/V2/Widgets/Service_Provider.php#L255 https://plugins.trac.wordpress.org/browser/the-events-calendar/tags/6.17.3/src/Tribe/Views/V2/Widgets/Service_Provider.php#L295 https://plugins.trac.wordpress.org/changeset?reponame=&old=3690576%40the-events-calendar&new=3690576%40the-events-calendar https://www.wordfence.com/threat-intel/vulnerabilities/id/a0c67346-534a-4b67-a904-fa148703707a?source=cve

Frequently Asked Questions

What is CVE-2026-78006? +

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. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-78006? +

CVE-2026-78006 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0078, placing it in the 1th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-78006? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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