Broken Access Control in My Calendar (<= 3.7.9) — What WordPress Site Owners Must Do Now

A low-severity but actionable broken access control vulnerability has been disclosed in the popular WordPress plugin “My Calendar” (Accessible Event Manager), affecting versions up to and including 3.7.9. The issue (CVE-2026-7525) permits an authenticated account with certain custom roles or modified capabilities to publish events without proper authorization checks. The vendor released a patched version (3.7.10).

From a Hong Kong operations and incident perspective: treat this seriously. Although an attacker must already hold an authenticated account, that access is enough to publish malicious events — used for spam, phishing, SEO abuse or reputational damage. This article explains the vulnerability, realistic risk scenarios, how to detect exploitation, immediate mitigations when you cannot patch immediately, and remediation steps after patching.

TL;DR — What you must do right now

• If you run My Calendar: update immediately to version 3.7.10 or later.
• If you cannot update immediately: apply temporary mitigations such as restricting access to event publication endpoints and hardening custom roles/capabilities.
• Audit for suspicious published events and check their authors. Remove malicious events and revoke or reset compromised accounts.
• Consider virtual patching via a Web Application Firewall (WAF) or server-side rule to block publish attempts by unauthorized users until you update.
• Rotate passwords for administrative accounts, enforce strong authentication, and run a full malware scan.

漏洞到底是什么？

The issue is a broken access control condition in My Calendar versions <= 3.7.9. A function responsible for publishing events does not perform reliable authorization checks (missing capability/nonce/role verification in some code paths). As a result, an authenticated user with a low-privilege or custom role may submit requests that set an event’s status to publish, making events public without the intended permission controls.

• An attacker must already have an authenticated account on the site (even low-privilege or custom role).
• The vulnerability does not allow unauthenticated remote takeover, but it enables an authenticated actor to escalate specific actions (publish events) when authorization is missing.
• The issue is patched in My Calendar 3.7.10 — update the plugin.

Although commonly assigned a low CVSS score, the real-world business risk depends on site traffic and audience. High-visibility calendars (government, education, NGOs) are attractive targets for spam, disinformation, or phishing campaigns.

可能的利用场景

Knowing how attackers could misuse this gives clarity on prioritisation:

1. Spam and SEO abuse — mass-published events containing links to spammy sites that get indexed and hurt SEO.
2. Phishing and drive-by scams — fake events with malicious links that appear legitimate because they are on your site.
3. 声誉损害 — offensive or fraudulent events published publicly.
4. 社会工程 — events that lure staff or users to malicious pages to harvest credentials.
5. Distribution of redirects — obfuscated links in event descriptions redirect users to malware or scam pages; these may propagate via feeds or digests.

Even without full admin escalation, the ability to publish content can cause significant harm.

Immediate detection checklist — scan and find suspicious indicators

If you run My Calendar, perform the following checks immediately.

1. Search for recently published events (WP-CLI)

# Find events published in the last 30 days
wp post list --post_type=mc_event --post_status=publish --format=csv --fields=ID,post_title,post_date,post_author | awk -F, -vDate="$(date -d '30 days ago' '+%Y-%m-%d')" 'BEGIN{OFS=","} NR==1{print $0; next} $3>=Date{print $0}'

Confirm the plugin’s post_type on your site if mc_event differs.

2. Look for published events created by low-privilege users (SQL)

SELECT p.ID, p.post_title, p.post_date, p.post_status, p.post_author, u.user_login, u.user_email
FROM wp_posts p
LEFT JOIN wp_users u ON p.post_author = u.ID
WHERE p.post_type = 'mc_event'
  AND p.post_status = 'publish'
  AND p.post_date >= DATE_SUB(NOW(), INTERVAL 30 DAY)
ORDER BY p.post_date DESC;

Review authorship: if low-privilege accounts are publishing, investigate those accounts immediately.

3. Audit recent role and capability changes

wp role list --format=json | jq .
# Check capabilities for specific roles:
wp role get  --fields=capabilities --format=json

Look for non-standard capabilities like publish_events assigned to non-admin roles.

4. Check server logs for suspicious POST calls

grep -R "event_status=publish" /var/log/nginx/* /var/log/apache2/* || true
grep -R "my-calendar" /var/log/nginx/* /var/log/apache2/* || true

Search for POSTs or AJAX calls that set event_status=publish or reference plugin endpoints.

5. Monitor outgoing email / notification systems

If event notifications are sent, review mail logs for messages about new events authored by unexpected users.

6. File and content checks

• Inspect event content for obfuscated URLs, scripts or redirects.
• Run your malware scanner against post content and media uploads.

If you find malicious events, export logs and database records before making changes to preserve evidence for post-incident analysis.

立即缓解措施（如果您无法立即更新）

If patch deployment is delayed, apply short-term mitigations to reduce risk.

1. Virtual patching with WAF or server rules

Deploy rules that block requests attempting to set event_status=publish or similar parameters from non-admin sessions. Virtual patching reduces exposure while you plan updates.

2. Restrict event publication to administrators only

Temporarily remove publishing capabilities from all non-admin roles. Example WP-CLI:

# Remove publish_events capability from a role called 'editor' (example)
wp role remove-cap editor publish_events

3. Disable frontend event submission

If the plugin offers frontend submissions, disable that feature or restrict the submission page to administrators until patched.

4. Deactivate the plugin temporarily (if practical)

If the calendar is non-essential for a short period, consider deactivating the plugin and presenting a static calendar or notice until patched and verified.

5. Enforce stronger login controls

Force password resets for accounts with publishing capability and enable two-factor authentication for privileged users.

6. Increase logging and monitoring

Raise log verbosity, add alerts for POST requests to plugin endpoints, and monitor for any attempts to create or publish events.

Conceptual WAF / server rule examples

Below are conceptual patterns to adapt to your environment. Test rules in staging prior to production deployment.

# Example ModSecurity-like rule (conceptual)
SecRule ARGS:event_status "@streq publish" "id:100001,phase:2,deny,log,msg:'Block attempt to publish My Calendar event by non-admin',chain"
    SecRule REQUEST_HEADERS:Cookie "!@contains wp-admin" "t:none"

# Example PHP check (theme functions.php) — stopgap only
add_action('init', function() {
    if (isset($_POST['event_status']) && $_POST['event_status'] === 'publish') {
        if (!current_user_can('manage_options')) {
            wp_die('Unauthorized', 'Forbidden', array('response' => 403));
        }
    }
});

Caveat: theme-level code edits are temporary and must be tested. Prefer plugin update or server-side virtual patching where possible.

修复和清理检查清单

After you update to My Calendar 3.7.10, follow these steps to ensure full remediation.

1. 更新插件： install 3.7.10+ and test on staging before production deploy.
2. Review and remove malicious events: export evidence, then remove or quarantine malicious events. Check email logs for recipients.
3. Audit user accounts and roles: identify accounts that published events, reset or disable suspicious accounts, and remove unexpected capabilities from custom roles.
4. 检查持久性/后门： scan for modified files, unknown admin users, suspicious cron jobs, or changed theme/plugin files.
5. Rotate credentials and API keys: if any keys or integrations may have been abused, rotate them.
6. Consider restore: if compromise is broad, restore from a verified clean backup.
7. 密切监控： increase logging and monitoring for at least 30 days after remediation.
8. 沟通： notify stakeholders and affected users if phishing or data exposure occurred.

减少未来暴露的加固建议

• 最小权限原则： only assign required capabilities to roles. Avoid giving publish rights to generic user roles.
• Regularly audit roles and capabilities using WP-CLI or management tools.
• Limit and vet third-party plugins; prefer actively maintained projects with clear release practices.
• Keep WordPress core, themes and plugins updated; test updates on staging where possible.
• Implement moderation workflows for user-submitted content so new items are reviewed before publication.
• Enforce strong authentication, password hygiene, and two-factor authentication for admin-level users.
• Maintain regular, tested backups with documented restore procedures.
• Consider virtual patching capabilities available in your infrastructure stack to reduce exposure windows.

Detection recipes and useful commands

Quick commands and queries for rapid triage.

Find events by non-admin users in last 7 days

SELECT p.ID, p.post_title, p.post_date, p.post_author, u.user_login, u.user_email, u.user_registered
FROM wp_posts p
JOIN wp_users u ON p.post_author = u.ID
WHERE p.post_type = 'mc_event'
  AND p.post_status = 'publish'
  AND p.post_date >= DATE_SUB(NOW(), INTERVAL 7 DAY)
ORDER BY p.post_date DESC;

List role capabilities (WP-CLI)

# Check capabilities for role:
wp role get author --fields=capabilities --format=json | jq .

Find event posts that contain external HTTP links

SELECT ID, post_title, post_author, post_date
FROM wp_posts
WHERE post_type = 'mc_event'
  AND post_content LIKE '%http://%'
  AND post_date >= DATE_SUB(NOW(), INTERVAL 30 DAY);

Search for recently modified PHP files

find /var/www/html -type f -mtime -7 -iname '*.php' -ls

事件响应手册（逐步）

If you confirm abuse, follow a structured response:

1. 控制： apply blocking rules, disable event submission features and force password resets for suspicious accounts.
2. 保留证据： export logs, database records and copies of malicious posts; record timestamps and request headers.
3. 根除： remove malicious events and files, update the plugin, tighten permissions and disable suspicious accounts.
4. 恢复： restore legitimate content from backups if needed; validate site functionality.
5. 事件后： run a full security audit, update response documentation and increase monitoring.

常见问题

问： If my site doesn’t allow user registration, am I safe?

答： Risk is lower but not zero. The vulnerability requires an authenticated account. If no external registrations exist and credentials are controlled, immediate risk is reduced. However, compromised or reused credentials could still be abused. Patch and monitor regardless.

问： Is this vulnerability exploitable without login?

答： No — an authenticated user is required.

问： I updated to 3.7.10; do I still need to check my site?

答： Yes. Updating prevents new exploit attempts, but you must audit for malicious events that may have been published before the patch.

Real-world indicators to watch for

• A surge of events with similar phrasing and outbound links posted within a short window.
• Published events authored by users who typically do not publish content (e.g., customers or low-privilege accounts).
• Event descriptions containing shortened/obfuscated URLs, base64 blobs, or HTML
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