The Events Calendar <= 6.17.4 — Unauthenticated PHP Object Injection to Remote Code Execution
CVE-2026-78006Published · Updated Action summary
Affected: ≤6.17.4Update to 6.17.4.1 or newer
All remediation steps- Severity
- Critical9.8
- CVSS
- 9.8CVSS 3.1 · CNA (Wordfence)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HWhat does this vector mean?
AV:NAttack vector- Network
AC:LAttack complexity- Low
PR:NPrivileges required- None
UI:NUser interaction- None
S:UScope- Unchanged
C:HConfidentiality- High
I:HIntegrity- High
A:HAvailability- High
- Weakness
- CWE-502 PHP Object Injection
- Required access
- No account needed
- Exploit prediction (EPSS)
- No score
- CISA KEV
- Not listed
On this page8
Am I affected?
The Events Calendar the-events-calendar
- Affected≤ 6.17.4
- Patched in6.17.4.1
Update to 6.17.4.1 or newer.
You are affected if you run ≤ 6.17.4. Version 6.17.4.1 and later are not affected by this issue.
- Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under The Events Calendar.
- No admin access? Run a passive check of your site. It reads public files only.
- No account is needed to exploit this. Treat any exposed site on an affected version as at risk.
What to do
- Update to version 6.17.4.1, or a newer patched version
- Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
- Watch The Events Calendar to get an email when the next vulnerability is published.
Advisory
Source description from Wordfence Intelligence, credited to Chloe Chamberland, Wordfence Argus.
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.
Exploits & references
Proof-of-concept & detection
No public proof-of-concept or detection template is known for this vulnerability.
Advisories & patches
- Advisorywordfence.com
Related CVEs
More in The Events Calendar
All 47| Severity | Vulnerability | CVE | Published |
|---|---|---|---|
| Medium6.4 | Authenticated (Contributor+) Stored Cross-Site Scripting ≤6.18.3Update to 6.18.3.1 | CVE-2026-123464 | |
| Medium6.5 | Unauthenticated Arbitrary Shortcode Execution ≤6.18.3Update to 6.18.3.1 | CVE-2026-123469 | |
| Medium4.3 | Missing Authorization ≤6.18.2Update to 6.18.3 | CVE-2026-119367 | |
| Medium6.4 | Authenticated (Contributor+) Stored Cross-Site Scripting ≤6.18.2Update to 6.18.3 | CVE-2026-119369 | |
| Medium5.3 | Missing Authorization ≤6.18.2Update to 6.18.3 | CVE-2026-119368 |
- Medium6.4Authenticated (Contributor+) Stored Cross-Site Scripting
≤6.18.3Update to 6.18.3.1
- Medium6.5Unauthenticated Arbitrary Shortcode Execution
≤6.18.3Update to 6.18.3.1
- Medium4.3Missing Authorization
≤6.18.2Update to 6.18.3
- Medium6.4Authenticated (Contributor+) Stored Cross-Site Scripting
≤6.18.2Update to 6.18.3
- Medium5.3Missing Authorization
≤6.18.2Update to 6.18.3
Same weakness (PHP Object Injection)
All PHP Object Injection| Severity | Vulnerability | CVE | Published |
|---|---|---|---|
| High7.2 | Unauthenticated Stored Cross-Site Scripting via Comment User-Agent Header | CVE-2026-120688 | |
| Critical9.8 | Unauthenticated Arbitrary File Upload via File Upload via Public Form Submission | CVE-2026-125055 | |
| Critical9.8 | Unauthenticated PHP Object Injection to Remote Code Execution via 'form' Parameter | CVE-2026-119077 | |
| Medium5.3 | Unauthenticated Sensitive Information Exposure in 'search' Parameter | CVE-2026-121518 |
- High7.2Unauthenticated Stored Cross-Site Scripting via Comment User-Agent Header
EZ SQL Reports Shortcode Widget and DB Backup
≤5.25.25Update to 5.26.45
- Critical9.8Unauthenticated Arbitrary File Upload via File Upload via Public Form Submission
Chatterbug Forms – Fast, Flexible WordPress Form Builder
≤1.0.2Update to 1.1
- Critical9.8Unauthenticated PHP Object Injection to Remote Code Execution via 'form' Parameter
ELEX WordPress HelpDesk & Customer Ticketing System
≤3.3.9Update to 3.4.0
- Medium5.3Unauthenticated Sensitive Information Exposure in 'search' Parameter
Customer Reviews for WooCommerce
≤5.127.0Update to 5.128.0
Timeline
CVE published
Severity critical, CVSS 9.8
Record last updated
Sources & licenses
Wordfence record- Vulnerability data
- Wordfence Intelligence. [object Object] Licensed under the CC BY-SA 4.0.
- CVE® identifiers
- [object Object]. Used under the CVE Program. CVE® is a registered trademark of The MITRE Corporation.
- CVSS / CWE
- National Vulnerability Database (NVD), shown unmodified. This product uses the NVD API but is not endorsed or certified by the NVD.
- VulnCrest content
- Summary, remediation guidance and page layout © VulnCrest. Not sourced from NVD.