CVE-2026-79423: SeaCMS v13.6 RCE Vulnerability

CVE-2026-79423 Overview

CVE-2026-79423 is an authenticated remote code execution (RCE) vulnerability in the admin_config.php component of SeaCMS v13.6. Attackers with valid administrative credentials can execute arbitrary code by sending a crafted POST request to the vulnerable endpoint. The flaw is categorized under [CWE-78] (Improper Neutralization of Special Elements used in an OS Command), indicating an OS command injection weakness. Successful exploitation grants attackers the ability to execute operating system commands in the context of the web server process, leading to full compromise of the underlying host.

Critical Impact
Authenticated attackers can execute arbitrary operating system commands on servers running SeaCMS v13.6, resulting in complete compromise of confidentiality, integrity, and availability.

Affected Products

SeaCMS v13.6
admin_config.php component
Deployments exposing the SeaCMS administrative interface

Discovery Timeline

2026-09-04 - CVE-2026-79423 published to the National Vulnerability Database (NVD)
2026-09-09 - Last updated in the NVD database

Technical Details for CVE-2026-79423

Vulnerability Analysis

The vulnerability resides in the admin_config.php component of SeaCMS v13.6, a PHP-based content management system used to build video and media portals. The component accepts POST request parameters that are passed to an operating system command execution context without proper neutralization. An authenticated attacker with access to the administrative panel can inject arbitrary shell metacharacters or commands into these parameters. The injected commands execute with the privileges of the PHP process, typically the web server user account.

Because the attack requires only low-privilege authenticated access and originates over the network, the vulnerability provides a straightforward path from administrative credential access to remote code execution. Compromise of a single administrator account is sufficient to reach full host compromise.

Root Cause

The root cause is improper neutralization of special elements used in an OS command [CWE-78]. The admin_config.php handler forwards user-supplied POST data into a command execution function (such as PHP's system, exec, shell_exec, passthru, or backtick operators) without sanitizing shell metacharacters. Attackers can inject characters such as ;, |, &&, or backticks to append arbitrary commands to the intended operation.

Attack Vector

The attack requires network access to the SeaCMS administrative interface and valid administrator credentials. The attacker submits a POST request to admin_config.php containing a payload embedded in a parameter that reaches the command execution sink. The injected commands run under the web server user context. See the GitHub Security Advisory CVE-2026-79423 and the SeaCMS Project Repository for additional technical details.

No verified public proof-of-concept code is currently linked from the enriched data, so exploitation mechanics are described in prose only.

Detection Methods for CVE-2026-79423

Indicators of Compromise

POST requests to /admin_config.php containing shell metacharacters such as ;, |, &, backticks, or $(...) in parameter values.
Unexpected child processes spawned by the PHP interpreter or web server user, including sh, bash, cmd.exe, powershell.exe, wget, curl, or nc.
New or modified files in the SeaCMS web root, particularly PHP web shells or scheduled task entries.
Outbound network connections from the web server to unknown external hosts following administrative activity.

Detection Strategies

Inspect web server access logs for POST requests to admin_config.php and correlate against administrator session activity and source IP addresses.
Monitor process ancestry to detect shell interpreters spawned by php-fpm, httpd, or nginx worker processes.
Deploy web application firewall (WAF) rules that flag command injection payloads in POST parameters bound for administrative endpoints.

Monitoring Recommendations

Enable verbose PHP execution logging on the SeaCMS host and forward logs to a centralized SIEM for correlation.
Alert on authentication events for administrator accounts from unfamiliar geographies or outside business hours.
Baseline outbound network traffic from the web server and alert on deviations that may indicate reverse shells or payload staging.

How to Mitigate CVE-2026-79423

Immediate Actions Required

Restrict network access to the SeaCMS administrative interface using IP allowlists, VPN, or reverse proxy authentication.
Rotate all administrator credentials and enforce strong, unique passwords with multi-factor authentication where the platform supports it.
Audit the SeaCMS web root for unauthorized files, backdoors, and modified PHP scripts.
Review web and application logs for prior exploitation attempts targeting admin_config.php.

Patch Information

At the time of publication, the enriched CVE data does not list a vendor-issued patch. Monitor the SeaCMS Project Repository and the GitHub Security Advisory CVE-2026-79423 for updated fix guidance and apply the vendor patch as soon as it becomes available.

Workarounds

Block external access to admin_config.php at the web server or WAF layer until a patch is applied.
Run the PHP process under a least-privilege account and disable dangerous functions such as system, exec, shell_exec, passthru, and proc_open in php.ini via the disable_functions directive.
Deploy WAF signatures that reject POST parameters containing shell metacharacters directed at the SeaCMS admin path.

bash

# Example php.ini hardening to reduce command execution surface
disable_functions = system,exec,shell_exec,passthru,proc_open,popen,pcntl_exec