CVE-2026-24523
Published: 23 January 2026
Summary
CVE-2026-24523 is a medium-severity Exposure of Sensitive System Information to an Unauthorized Control Sphere (CWE-497) vulnerability. Its CVSS base score is 5.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique System Information Discovery (T1082); ranked at the 3.0th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 AC-3 (Access Enforcement) and AC-4 (Information Flow Enforcement).
Deeper analysis
CVE-2026-24523 is an Exposure of Sensitive System Information to an Unauthorized Control Sphere vulnerability (CWE-497) in the WP FullCalendar WordPress plugin, developed by Marcus (aka @msykes) and known as wp-fullcalendar. The flaw allows retrieval of embedded sensitive data and affects all versions from n/a through 1.6 inclusive. Published on 2026-01-23, it carries a CVSS v3.1 base score of 5.3 (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N), indicating medium severity with low-impact confidentiality loss.
The vulnerability can be exploited by any unauthenticated attacker over the network with low complexity and no user interaction required. Exploitation enables retrieval of embedded sensitive data exposed to an unauthorized control sphere, resulting in limited disclosure of confidential system information without impacting integrity or availability.
The Patchstack advisory at https://patchstack.com/database/Wordpress/Plugin/wp-fullcalendar/vulnerability/wordpress-wp-fullcalendar-plugin-1-6-sensitive-data-exposure-vulnerability?_s_id=cve details this sensitive data exposure issue in WP FullCalendar version 1.6 and related versions.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-4392
Vulnerability details
Exposure of Sensitive System Information to an Unauthorized Control Sphere vulnerability in Marcus (aka @msykes) WP FullCalendar wp-fullcalendar allows Retrieve Embedded Sensitive Data.This issue affects WP FullCalendar: from n/a through <= 1.6.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The CVE describes unauthenticated network exposure of sensitive system information via a public-facing WordPress plugin, directly enabling System Information Discovery (T1082) and initial access via public application exploitation (T1190).
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Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly enforces access control policies so that unauthenticated remote users cannot retrieve the embedded sensitive data exposed by the WP FullCalendar plugin.
Enforces information-flow rules that keep sensitive system data inside its authorized control sphere and block the unauthorized retrieval described in CVE-2026-24523.
Requires cryptographic or other protection of sensitive information at rest, reducing the impact if the plugin’s embedded data is stored in a publicly accessible location.