{"id":"CVE-2026-40308","state":"PUBLISHED","title":"My Calendar: Unauthenticated Information Disclosure (IDOR) via Multisite switch_to_blog","description":"My Calendar is a WordPress plugin for managing calendar events. In versions 3.7.6 and below, the mc_ajax_mcjs_action AJAX endpoint, registered for unauthenticated users, passes user-supplied arguments through parse_str() without validation, allowing injection of arbitrary parameters including a site value. On WordPress Multisite installations, this enables an unauthenticated attacker to call switch_to_blog() with an arbitrary site ID and extract calendar events from any sub-site on the network, including private or hidden events. On standard Single Site installations, switch_to_blog() does not exist, causing an uncaught PHP fatal error and crashing the worker thread, creating an unauthenticated denial of service vector. This issue has been fixed in version 3.7.7.","publishedAt":"2026-04-16T21:30:52.401Z","updatedAt":"2026-04-17T12:32:26.622Z","severity":{"score":8.8,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["joedolson my-calendar"],"affected":[{"vendor":"joedolson","product":"my-calendar","versions":[{"version":"< 3.7.7","status":"affected"}]}],"references":["https://github.com/joedolson/my-calendar/security/advisories/GHSA-2mvx-f5qm-v2ch","https://github.com/joedolson/my-calendar/releases/tag/v3.7.7"],"weaknesses":["CWE-639"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/40xxx/CVE-2026-40308.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-40308","state":"PUBLISHED","datePublished":"2026-04-16T21:30:52.401Z","dateUpdated":"2026-04-17T12:32:26.622Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-04-10T21:41:54.504Z"},"containers":{"cna":{"title":"My Calendar: Unauthenticated Information Disclosure (IDOR) via Multisite switch_to_blog","descriptions":[{"lang":"en","value":"My Calendar is a WordPress plugin for managing calendar events. In versions 3.7.6 and below, the mc_ajax_mcjs_action AJAX endpoint, registered for unauthenticated users, passes user-supplied arguments through parse_str() without validation, allowing injection of arbitrary parameters including a site value. On WordPress Multisite installations, this enables an unauthenticated attacker to call switch_to_blog() with an arbitrary site ID and extract calendar events from any sub-site on the network, including private or hidden events. On standard Single Site installations, switch_to_blog() does not exist, causing an uncaught PHP fatal error and crashing the worker thread, creating an unauthenticated denial of service vector. This issue has been fixed in version 3.7.7."}],"affected":[{"vendor":"joedolson","product":"my-calendar","versions":[{"version":"< 3.7.7","status":"affected"}]}],"references":[{"url":"https://github.com/joedolson/my-calendar/security/advisories/GHSA-2mvx-f5qm-v2ch","name":"https://github.com/joedolson/my-calendar/security/advisories/GHSA-2mvx-f5qm-v2ch","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/joedolson/my-calendar/releases/tag/v3.7.7","name":"https://github.com/joedolson/my-calendar/releases/tag/v3.7.7","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":8.8,"baseSeverity":"HIGH","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-639","lang":"en","description":"CWE-639: Authorization Bypass Through User-Controlled Key","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-04-16T21:30:52.401Z"},"source":{"advisory":"GHSA-2mvx-f5qm-v2ch","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/joedolson/my-calendar/security/advisories/GHSA-2mvx-f5qm-v2ch","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-04-17T12:32:21.737938Z","id":"CVE-2026-40308","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-04-17T12:32:26.622Z"}}]}}}