CVE-2026-78006
CRITICALDescription
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.
How to fix
No published remediation has been found for this vulnerability's affected products yet.
Mitigation guidance may be in the linked vendor advisories in the References section below.
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CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
Moderate risk: more likely to be exploited than 54% of all known CVEs.
References
Related Vulnerabilities
Other CWE-502 (Deserialization of Untrusted Data) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2023-0669 | High | 7.2 | 100% | KEV + Ransom | Fix |
| CVE-2021-44228 | Critical | 10.0 | 100% | KEV + Ransom | Fix |
| CVE-2021-35464 | Critical | 9.8 | 100% | KEV + Ransom | Fix |
| CVE-2025-53770 | Critical | 9.8 | 100% | KEV + Ransom | Fix |
| CVE-2023-29300 | Critical | 9.8 | 100% | KEV + Ransom | - |
| CVE-2025-59287 | Critical | 9.8 | 100% | KEV | Fix |
Common questions
How do I fix CVE-2026-78006?
No published fix for CVE-2026-78006 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
Is CVE-2026-78006 being actively exploited?
Not that we know of. CVE-2026-78006 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.78% is the estimated probability that it will be exploited in the next 30 days. That is higher than 54% of all scored CVEs.
How severe is CVE-2026-78006?
CVE-2026-78006 has a CVSS v3 base score of 9.8, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-14.