Privilege Escalation in My Calendar – Accessible Event Manager (WordPress plugin) (CVE-2026-104798)
Summary
Vulnerability in My Calendar – Accessible Event Manager (WordPress plugin) (CVE-2026-104798). Successful exploitation can lead to full system takeover. Exploitable via mcs.
Original description
The description as published by the source.
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. 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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-104798 has been found in My Calendar – Accessible Event Manager (WordPress plugin).
Attackers can target a specific entry point like mcs over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 9.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "My Calendar – Accessible Event Manager (WordPress plugin) CVE-2026-104798" on the vendor's site.
CVE-2026-104798 (My Calendar – Accessible Event Manager (WordPress plugin)) — CWE-269 / CVSS v3 9.8
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: mcs / do_shortcode / above
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-269) exists in My Calendar – Accessible Event Manager (WordPress plugin). Attackers reach the vulnerable code path via mcs without authentication.
Check the vendor advisory for the affected versions of My Calendar – Accessible Event Manager (WordPress plugin). Attack surface: mcs / do_shortcode / above.
Severity: Critical (CVSS 9.8/10). Successful exploitation can lead to full system takeover.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで My Calendar – Accessible Event Manager (WordPress plugin) を使っているサービスとバージョンを洗い出す。
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2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。