CVE-2026-6854 SQL Injection in My Calendar – Accessible Event Manager Plugin

Technical summary

CVE-2026-6854 is a time-based blind SQL injection vulnerability in the My Calendar – Accessible Event Manager plugin. The flaw stems from insufficient input validation and lack of parameterized query preparation for the 'mc_auth' parameter. Attackers craft requests that break out of the existing SQL query context and append arbitrary SQL commands, enabling data exfiltration through timing-based inference (blind injection). The vulnerability maps to CWE-89 (SQL Injection) and carries a CVSS v3.1 score of 7.5 (High), reflecting high confidentiality impact via unauthenticated network access with no privilege requirements.

Business impact

Organizations running My Calendar versions up to 3.7.8 face exposure of database contents, including user credentials, configuration secrets, customer records, and other sensitive information stored in their WordPress databases. Because exploitation requires no authentication, any threat actor on the internet can attempt attacks. Data breach notification obligations, regulatory penalties, and reputational harm may follow if customer or employee data is compromised. Website availability is not directly impacted by this vulnerability, but unauthorized data access can lead to further attacks if extracted credentials are leveraged.

Affected systems

The My Calendar – Accessible Event Manager WordPress plugin in versions up to and including 3.7.8 is affected. This includes all installations that have not applied a patch beyond 3.7.8. Any WordPress site using this plugin is potentially vulnerable unless the site-owner has manually applied mitigations such as Web Application Firewall rules or has already upgraded to a patched version.

Exploitability

This vulnerability is straightforward to exploit. No authentication is required, and exploitation can be performed over the network without user interaction. Time-based blind SQL injection does require attacker patience and methodology—extracting data character-by-character through response timing is slower than union-based or error-based injection—but modern automated tools and publicly available proof-of-concept code make this practical for real-world attacks. The attack vector is network-accessible and requires no special conditions.

Remediation

Upgrade My Calendar – Accessible Event Manager to a version patched after 3.7.8 (verify the exact patched version against the plugin's official release notes or vendor advisory). If an immediate upgrade is not possible, disable or remove the plugin entirely until a fix can be deployed. Monitor WordPress plugin repositories and vendor communications for patch availability. As a temporary measure, use a Web Application Firewall to filter requests containing suspicious SQL keywords in the 'mc_auth' parameter, though this is not a substitute for patching.

Patch guidance

Check the My Calendar plugin vendor's official WordPress.org plugin page and security advisories for a patched version released after July 8, 2026. Deploy the update through the WordPress admin dashboard once available. Verify in your WordPress site that the plugin version has been incremented beyond 3.7.8. Test the plugin's core functionality after patching to ensure no regression. If the vendor has not yet released a patch, contact them or consider temporarily disabling the plugin.

Detection guidance

Monitor web server access logs for requests containing the 'mc_auth' parameter combined with SQL keywords (e.g., UNION, SELECT, OR, SLEEP, BENCHMARK). Look for repeated requests with slight variations, characteristic of blind SQL injection probing. WordPress security plugins may detect and log exploitation attempts if they include SQL injection pattern matching. Implement database activity monitoring to detect suspicious query patterns or unauthorized access attempts. Time-based blind injection will show as many requests in short succession followed by delayed responses—this traffic pattern can be flagged for review.

Why prioritize this

This vulnerability merits immediate attention due to its high CVSS score (7.5), unauthenticated attack vector, and ease of exploitation. Any data exfiltration exposes business-critical and personal information. The wide attack surface (all versions through 3.7.8) and straightforward exploitation path make this a primary target for threat actors. While not currently listed on CISA's KEV catalog, the combination of high impact and low barrier to entry makes it a priority for patch planning.

Risk score, explained

The CVSS v3.1 score of 7.5 (High) reflects the vulnerability's characteristics: network-accessible attack vector (AV:N), low complexity (AC:L), no privilege or user interaction required (PR:N/UI:N), and high confidentiality impact (C:H). Integrity and availability are not compromised, limiting the score below Critical. The overall rating is commensurate with a database breach risk requiring urgent remediation.

Frequently asked questions