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CVE-2026-104798

Status: DeferredCritical (9.8)—
Severity9.8Critical · CVSS 3.1
Exploitation probability0.89 %higher than 59% of CVEs
Active exploitationNonot in the CISA catalog
Public exploitNot knownno public code found

The My Calendar – Accessible Event Manager plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 3.8.7. The public `mcs` GET parameter is reflected into post content unsanitized before WordPress core's `do_shortcode` filter runs, allowing an unauthenticated attacker to inject a nested `[my_calendar above=...]` shortcode; `mc_generate_calendar_nav()` then splits the `above` attribute on commas and dispatches each element via `call_user_func()` with no authentication, authorization, or callable allowlist check.

Read full descriptionShow less

This makes it possible for unauthenticated attackers to invoke arbitrary loaded PHP functions, enabling a call chain in which the shortcode `$params` array is passed to `edit_user()` — which PHP coerces to integer `1` as the `$user_id` argument — overwriting the credentials of the initial Administrator account (user ID 1) and granting the attacker full wp-admin access. Exploitation is trivially reachable via the plugin's auto-generated `/my-calendar/` page, which is publicly accessible by default upon plugin activation.

CVSS

Base score
9.8
Version
3.1
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days
0.89 %
Percentile among all scored CVEs
59
Score date
10/20/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

Vector AV:N/PR:N/UI:N sin autenticación; vía shortcode inyectado se invocan funciones PHP arbitrarias y edit_user() sobrescribe las credenciales del administrador ID 1, dando acceso wp-admin.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

ATT&CK mitigations that cover these techniques

Privileged Account ManagementNetwork SegmentationApplication Isolation and SandboxingExploit ProtectionUpdate SoftwareVulnerability Scanning

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Joedolson — MY CalendarAI

CWEs

References

Show 8 references

Raw JSON (NVD)

Show
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  "lastModified": "2026-10-16T18:17:20.360",
  "sourceIdentifier": "security@wordfence.com"
}