CVE-2026-19231: Simple Doctors Appointment System SQLi

CVE-2026-19231 Overview

CVE-2026-19231 is a SQL injection vulnerability in SourceCodester Simple Doctors Appointment System 1.0. The flaw resides in /admin/ajax.php?action=delete_appointment, where the ID parameter is passed unsanitized to a database query. Attackers can exploit the issue remotely without authentication. Public exploit details have been released, increasing the likelihood of opportunistic abuse against exposed instances. The weakness is classified under CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component.

Critical Impact
Remote, unauthenticated attackers can manipulate backend SQL queries through the ID parameter, exposing appointment data and potentially the entire application database.

Affected Products

SourceCodester Simple Doctors Appointment System 1.0
Administrative endpoint /admin/ajax.php?action=delete_appointment
Deployments exposing the admin interface to untrusted networks

Discovery Timeline

2026-08-07 - CVE-2026-19231 published to NVD
2026-08-12 - Last updated in NVD database

Technical Details for CVE-2026-19231

Vulnerability Analysis

The vulnerability affects the delete_appointment action handler inside /admin/ajax.php. The handler accepts an ID parameter from the HTTP request and incorporates it into a SQL DELETE statement without parameterization or input sanitization. Attackers who supply crafted values for ID can break out of the intended query context and execute additional SQL statements. Because the endpoint is reachable over the network and requires no prior authentication in the vulnerable configuration, exploitation can occur remotely with minimal effort. Public disclosure through VulDB entry 386995 and the associated GitHub issue provides adversaries with sufficient detail to weaponize the flaw.

Root Cause

The root cause is missing input validation and the absence of prepared statements in the appointment deletion routine. User-controlled input flows directly into an SQL query string, allowing operators and syntax to be injected. This pattern is a classic instance of [CWE-74] and reflects unsafe query construction throughout the application.

Attack Vector

An attacker sends an HTTP request to the vulnerable endpoint with a malicious payload appended to the ID parameter. Payloads using boolean, time-based, or UNION-based techniques can enumerate database schema, extract stored records, or manipulate application state. The attack requires no user interaction and can be automated with commodity tooling.

No verified exploit code is included in this article. Refer to the VulDB advisory for public technical details.

Detection Methods for CVE-2026-19231

Indicators of Compromise

HTTP requests to /admin/ajax.php?action=delete_appointment containing SQL metacharacters such as single quotes, UNION, SLEEP(, or comment sequences in the ID parameter.
Unexpected DELETE operations against the appointments table originating from the web application user.
Web server access logs showing repeated requests to the delete_appointment action from a single source with varying ID values.

Detection Strategies

Deploy a web application firewall rule that inspects the ID parameter for non-numeric input and known SQL injection signatures.
Enable database query logging and alert on syntactically anomalous statements referencing the appointments table.
Correlate anonymous or unauthenticated access to /admin/ajax.php with elevated error rates from the database tier.

Monitoring Recommendations

Monitor outbound traffic from the web server for unusual data volumes that may indicate database exfiltration.
Track authentication state on admin endpoints and alert when unauthenticated sessions reach /admin/ajax.php.
Review PHP error logs for SQL syntax errors that indicate probing attempts against the vulnerable action.

How to Mitigate CVE-2026-19231

Immediate Actions Required

Restrict network access to the /admin/ directory using IP allowlisting or authentication proxies until a patch is available.
Audit application logs for prior requests to /admin/ajax.php?action=delete_appointment containing suspicious ID values.
Rotate database credentials used by the application if compromise is suspected.

Patch Information

No official vendor patch has been published for SourceCodester Simple Doctors Appointment System 1.0 at the time of writing. Administrators should track the SourceCodester project page and the GitHub issue tracker for remediation guidance. Applying a source-level fix requires replacing string concatenation with parameterized queries in the delete_appointment handler and enforcing server-side type checking on the ID argument.

Workarounds

Modify /admin/ajax.php to cast the ID parameter to an integer using intval() before it reaches any SQL statement.
Introduce a prepared statement using PDO or MySQLi bound parameters in place of direct string interpolation.
Place the administrative interface behind a VPN or reverse proxy that enforces authentication before requests reach PHP.

bash

# Example WAF rule (ModSecurity) blocking non-numeric ID values on the vulnerable endpoint
SecRule REQUEST_URI "@contains /admin/ajax.php" \
    "chain,phase:2,deny,status:403,id:1026192310,msg:'CVE-2026-19231 SQLi attempt'"
    SecRule ARGS:action "@streq delete_appointment" "chain"
    SecRule ARGS:ID "!@rx ^[0-9]+$"