Description

Unauthenticated Cross Site Request Forgery (CSRF) in Simply Schedule Appointments <= 1.6.12.23 versions.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.8",
  "pubDate": "2026-09-02T12:17:14.800Z",
  "pubdate": "2026-09-02T12:17:14.800Z",
  "executiveSummary": "A Cross-Site Request Forgery (CSRF) vulnerability exists in Simply Schedule Appointments versions 1.6.12.23 and earlier. This security flaw allows an unauthenticated, remote attacker to trick an authenticated administrative user into performing unintended actions within the WordPress environment.\nThe vulnerability arises from the absence of appropriate nonce validation or anti-CSRF tokens within the plugin's request handling mechanisms. By coercing an administrator's browser into executing malicious HTTP requests, the attacker can manipulate plugin configurations, potentially leading to unauthorized data modification or administrative state changes.\nBecause the attack relies on the victim's session, the exploitation requirements include social engineering—such as inducing an administrator to visit a malicious website or click a crafted link while logged into the WordPress dashboard. The risk implication is significant as it bypasses authorization controls, potentially allowing an attacker to modify scheduling settings or trigger internal plugin functions without the user's consent. This flaw falls under the CWE-352: Cross-Site Request Forgery classification. Immediate action is required to mitigate the risk, primarily through updating the plugin to a patched version once available.",
  "technicalDetails": "The root cause of this vulnerability is the failure of the Simply Schedule Appointments plugin to implement state-changing request verification. In a secure web application, operations that perform modifications—such as saving settings, deleting entries, or modifying database records—must verify that the request originated from the intended user interface rather than a third-party source.\nWithout the implementation of a cryptographically secure nonce or a similar anti-CSRF token, the application cannot distinguish between a legitimate request initiated by the administrator and an unauthorized request forged by an attacker. The vulnerable component operates by accepting HTTP GET or POST requests that trigger internal handler functions without checking the integrity or origin of the request payload.\nThe exploitation flow proceeds as follows: 1. The attacker crafts a malicious payload, typically embedded within a hidden HTML form or a script, designed to send a request to the WordPress administrative dashboard that targets a specific endpoint within the Simply Schedule Appointments plugin. 2. The attacker induces a target administrator to interact with the malicious resource (e.g., via a phishing link or an injected advertisement on a compromised site). 3. Upon loading, the victim's browser automatically appends the relevant session cookies associated with the authenticated WordPress session to the crafted request. 4. The server receives the request, associates it with the administrator’s session, and executes the plugin function because no nonce validation is performed to challenge the request's origin. 5. The plugin processes the request and executes the targeted administrative action as if it were an authorized request by the user.\nThe lack of authentication requirements for the initial trigger makes this a potent attack vector, as the attacker does not require prior access to the system. The post-exploitation impact allows for the manipulation of the application state, which, depending on the vulnerable plugin endpoints exposed, could lead to further configuration compromise, unauthorized modification of scheduling logic, or, in some scenarios, the modification of data that impacts availability or confidentiality of the appointment system.\nBecause the issue resides within the core processing logic of the plugin, all versions up to and including 1.6.12.23 are considered affected. The vulnerability relies entirely on the authenticated state of the victim's session; therefore, any administrative user active in the same browser context is susceptible to the CSRF execution."
}