CVE-2026-77187 joedolson CVE debrief

Who should care

WordPress administrators and security teams should assess exposure and prioritize updates for My Calendar – Accessible Event Manager plugin versions up to 3.8.3. They should also review compensating controls for exposed systems while remediation is scheduled and verified, and track exceptions, retest remediated assets, and close the item only after evidence is documented.

Why it matters

CVE-2026-77187 is a Stored Cross-Site Scripting vulnerability in the My Calendar – Accessible Event Manager plugin for WordPress. It allows authenticated attackers with contributor-level access to inject web scripts, potentially leading to user session hijacking or unauthorized actions. WordPress administrators and security teams should assess exposure and prioritize updates.

• Attackers can inject arbitrary web scripts in pages, potentially leading to user session hijacking or unauthorized actions.
• Successful exploitation requires contributor-level access and above, which may be more easily compromised.
• The vulnerability has a CVSS score of 6.4 and MEDIUM severity, indicating a moderate risk.

Technical summary

The My Calendar – Accessible Event Manager plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'before' and 'after' Shortcode Attributes in all versions up to, and including, 3.8.3. This is due to insufficient input sanitization and output escaping, allowing authenticated attackers with contributor-level access and above to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Defensive priority

Medium-priority defensive review recommended for WordPress installations using My Calendar – Accessible Event Manager plugin versions up to 3.8.3, focusing on contributor-level access and above.

Recommended defensive actions

• Review and update My Calendar – Accessible Event Manager plugin to a version beyond 3.8.3 if possible.
• Restrict contributor-level access and above to trusted users.
• Monitor for suspicious page accesses and injected scripts.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.
• Check relevant monitoring, detection, and logs for exposed assets that need extra review.

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its CVSS score of 6.4 and MEDIUM severity. Contributor-level access and above can inject arbitrary web scripts. The My Calendar – Accessible Event Manager plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'before' and 'after' Shortcode Attributes in all versions up to, and including, 3.8.3 due to insufficient input sanitization and output escaping. This information is based on the CVE record and NVD entry, which provide official details on

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.