# CVE-2026-78159: The Events Calendar <= 6.17.3 - Unauthenticated Code Injection to Remote Code Execution via Widget 'classes' Map Callable Invocation

- Exploited (CISA KEV): no
- Published: 2026-09-12
- CVSS: 9.8 CRITICAL (v3.1)
- EPSS: 1.4% (72th percentile)
- CWE: CWE-94

The The Events Calendar plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 6.17.3 via the parse_array function. This is due to insufficient validation of the widget 'classes' map, allowing a plain-array payload to bypass the is_safe_widget_instance() object check and reach the callable-invocation sink in Element_Classes::parse_array(). This makes it possible for unauthenticated attackers to execute code on the server. Exploitation requires that the targeted site has comments enabled on tribe_events posts and that at least one comment containing a crafted wp:legacy-widget block has been submitted, as the attack chain is triggered when do_blocks() processes the single-event HTML including the comment area.

## Edge WAF coverage (claimed by vendors, not measured)

| Vendor | Status | First rule | Days after publication |
|---|---|---|---|
| Cloudflare | No public claim | — | — |
| AWS | No public claim | — | — |
| Microsoft Azure | No public claim | — | — |
| Google Cloud | No public claim | — | — |
| Fastly | Before feed history | — | — |
| F5 | Rule published | 2026-10-21 | 39 |
| Akamai | No public source | — | — |
| OWASP CRS | No public claim | — | — |

### F5

- 2026-10-21 · new · rule 200204107
  > Added: signature 200204107 "WordPress The Events Calendar Unauthenticated RCE" (Server Side Code Injection, risk High), systems: WordPress. References: CVE-2026-78006, CVE-2026-78159.
  Source: https://docs.cloud.f5.com/docs-v2/platform/changelogs/security-details-changelog

"No public claim" means no vendor statement names this CVE; "Before feed history" means the CVE is older than the vendor feed. In both cases generic rules may still block it.

HTML: https://cve.vigilbase.com/cve/CVE-2026-78159 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2026-78159