{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","feed_url":"https://feed.craftedsignal.io/tags/cve-2026-55651/feed.json","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cpes":[],"_cs_cves":[{"cvss":7.1,"id":"CVE-2026-55651"}],"_cs_exploited":false,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":["Easy!Appointments (1.5.2)"],"_cs_severities":["medium"],"_cs_tags":["web-application","cve-2026-55651","access-control"],"_cs_type":"advisory","_cs_vendors":["Easy!Appointments"],"content_html":"\u003cp\u003eEasy!Appointments version 1.5.2 is affected by an excessive data exposure vulnerability (CVE-2026-55651) within its customer search functionality. The flaw originates from the application's failure to perform object-level authorization checks on the '/customers/search' endpoint. An authenticated user can trigger a search request and receive response objects that include unique appointment hashes belonging to other providers and customers.\u003c/p\u003e\n\u003cp\u003eBy harvesting these identifiers, an attacker can interact with appointment management endpoints to perform unauthorized actions. Because the system lacks verification that the authenticated user owns the appointment referenced by a given hash, an attacker can effectively perform an 'Appointment Takeover.' This enables the unauthorized modification of appointment details, such as changing the assigned provider, or the outright deletion/cancellation of third-party appointments. This vulnerability highlights critical weaknesses in access control and data filtering within the appointment management lifecycle.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAttacker authenticates to the Easy!Appointments instance as a valid user or provider.\u003c/li\u003e\n\u003cli\u003eAttacker initiates an HTTP POST request to the '/customers/search' endpoint.\u003c/li\u003e\n\u003cli\u003eThe application returns an JSON response containing customer and appointment data, including the appointment hashes of appointments belonging to other users.\u003c/li\u003e\n\u003cli\u003eAttacker parses the response to extract the target appointment hash.\u003c/li\u003e\n\u003cli\u003eAttacker makes an HTTP request to '/calendar/reschedule/{hash}' using the harvested hash.\u003c/li\u003e\n\u003cli\u003eApplication fails to validate ownership of the appointment hash, granting the attacker access to the appointment's administrative context.\u003c/li\u003e\n\u003cli\u003eAttacker modifies the appointment provider or cancels/deletes the appointment, resulting in complete appointment takeover.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation results in unauthorized modification or deletion of appointments across the platform. This leads to operational disruption, loss of service availability for victims, and a breach of data confidentiality. The impact is significant for organizations relying on the platform to manage sensitive scheduling and customer information, as attackers can silently reassign or cancel appointments without the legitimate provider's knowledge.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cp\u003eDetection engineering teams should monitor web server access logs for anomalous patterns related to the vulnerable endpoints. Prioritize the following actions:\u003c/p\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy WAF rules or application-level monitoring to alert on high-frequency requests to '/customers/search' by non-administrative accounts.\u003c/li\u003e\n\u003cli\u003eImplement logging for all requests to '/calendar/reschedule/*' and cross-reference the attempted hash against the user's authorized appointment list.\u003c/li\u003e\n\u003cli\u003ePatch the instance to the version that remediates CVE-2026-55651, as the vulnerability requires code-level fixes to implement strict object-level authorization.\u003c/li\u003e\n\u003cli\u003eMonitor for 200 OK responses to '/customers/search' that return a disproportionately high number of appointment records relative to the authenticated user's scope.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-07-29T16:23:37Z","date_published":"2026-07-29T16:23:37Z","id":"https://feed.craftedsignal.io/briefs/2026-07-easyappointments-takeover/","summary":"An excessive data exposure vulnerability in Easy!Appointments version 1.5.2 allows authenticated attackers to retrieve sensitive appointment hashes and hijack other providers' appointments.","title":"Easy!Appointments Excessive Data Exposure and Appointment Takeover","url":"https://feed.craftedsignal.io/briefs/2026-07-easyappointments-takeover/"}],"language":"en","title":"CraftedSignal Threat Feed - Cve-2026-55651","version":"https://jsonfeed.org/version/1.1"}