# CVE-2026-78006: The Events Calendar remote code execution via unserialization

Source: https://junglewise.ai/threats/cve-2026-78006-the-events-calendar-remote-code-execution-via-unserialization  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-12. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-78006 · Severity: critical · CVSS 9.8 · Published 2026-09-12

The Events Calendar is a popular WordPress plugin for managing event pages and content. A flaw in its widget validation allows unauthenticated attackers to inject malicious code through event comments, which is then executed on the server. An attacker can exploit this without needing to log in or have their comment approved, directly compromising the website and potentially allowing full server takeover.

## Quick answers

**Is CVE-2026-78006 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-78006 being exploited in the wild.

**How severe is CVE-2026-78006?** Critical severity, with a CVSS score of 9.8, published 12 September 2026.

**Which products and versions are affected?** Modern Tribe The Events Calendar up to and including 6.17.4.

**Is there a fix for CVE-2026-78006?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-78006 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-78006?** Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a PHP object injection and remote code execution flaw in the is_safe_widget_instance() function. The root cause is insufficient validation before unserialize() is called, combined with enable_rendering_widget_copied() forging a valid wp_hash integrity check. An attacker can bypass the safety checks by leveraging PHP magic methods invoked during parsing, then inject malicious serialized objects through event comment HTML. The V2 single-event template runs do_blocks() over buffered comments and returns a moderation-hash URL, allowing unauthenticated commenters to immediately view their pending comment. This delivers the injected block markup to the vulnerable code path before moderation occurs. Exploitation requires comments to be enabled on events. Patches are available in versions after 6.17.4.

## Affected products

- Modern Tribe The Events Calendar up to and including 6.17.4

## Timeline

- 2026-09-12: disclosed

## References

- [https://plugins.trac.wordpress.org/browser/the-events-calendar/tags/6.17.3/common/src/Tribe/Utils/Collection_Trait.php](https://plugins.trac.wordpress.org/browser/the-events-calendar/tags/6.17.3/common/src/Tribe/Utils/Collection_Trait.php)
- [https://plugins.trac.wordpress.org/browser/the-events-calendar/tags/6.17.3/src/Tribe/Collections/Lazy_Post_Collection.php](https://plugins.trac.wordpress.org/browser/the-events-calendar/tags/6.17.3/src/Tribe/Collections/Lazy_Post_Collection.php)