CVE-2026-48836: Easy Invoice RCE Vulnerability

CVE-2026-48836 Overview

CVE-2026-48836 is an unauthenticated Remote Code Execution (RCE) vulnerability affecting the Easy Invoice WordPress plugin in versions up to and including 2.1.19. The flaw is classified under [CWE-94] Improper Control of Generation of Code (Code Injection). Remote attackers can execute arbitrary code on the underlying server without authentication or user interaction. Successful exploitation allows full compromise of the WordPress site and the hosting environment. The vulnerability carries a maximum CVSS 3.1 base score of 10.0, reflecting network attack vector, no privileges required, and a changed scope with full confidentiality, integrity, and availability impact.

Critical Impact
Unauthenticated attackers can execute arbitrary code remotely on WordPress sites running Easy Invoice 2.1.19 or earlier, leading to complete site and server compromise.

Affected Products

WordPress Easy Invoice plugin versions <= 2.1.19
WordPress sites with the vulnerable plugin installed and active
Hosting environments serving the affected WordPress installations

Discovery Timeline

2026-06-15 - CVE-2026-48836 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2026-48836

Vulnerability Analysis

The vulnerability resides in the Easy Invoice WordPress plugin and stems from improper control of code generation, mapped to [CWE-94]. The plugin accepts attacker-supplied input that flows into a code execution sink without sanitization or authentication checks. Network-based attackers can invoke the vulnerable endpoint directly. Because no privileges or user interaction are required, exploitation is straightforward and can be automated against exposed WordPress sites. The scope change in the CVSS vector indicates that exploitation impacts resources beyond the vulnerable component, reflecting the ability to pivot from the plugin context to the wider WordPress installation and host operating system.

Root Cause

The root cause is improper neutralization of user-controlled input that is later interpreted as code by the PHP runtime. The plugin fails to enforce capability checks or nonce validation on the affected request handler. This combination of missing authorization and unsafe code generation enables direct command execution as the web server user. Refer to the Patchstack RCE Vulnerability Report for the technical breakdown.

Attack Vector

The attack vector is network-based and unauthenticated. An attacker sends a crafted HTTP request to a vulnerable Easy Invoice plugin endpoint on a WordPress site. The malicious payload reaches the unsafe code generation sink and is executed by the PHP interpreter. The attacker gains code execution under the privileges of the web server process. From there, attackers typically deploy webshells, exfiltrate database credentials from wp-config.php, or pivot deeper into the hosting environment.

No verified public proof-of-concept code is currently linked in NVD. The EPSS score is 0.572% with a percentile of 42.756 as of 2026-06-18, indicating moderate near-term exploitation likelihood that may rise as details become public.

Detection Methods for CVE-2026-48836

Indicators of Compromise

Unexpected PHP files created in the wp-content/uploads/ or wp-content/plugins/easy-invoice/ directories
Outbound network connections from the web server to unfamiliar IP addresses shortly after suspicious POST requests
New or modified administrative WordPress user accounts that cannot be attributed to legitimate activity
Web server processes spawning shell interpreters such as /bin/sh, bash, or cmd.exe

Detection Strategies

Inspect web server access logs for POST requests to Easy Invoice plugin endpoints originating from unauthenticated sessions
Monitor for PHP process executions of system(), exec(), passthru(), or eval() patterns in application logs
Deploy file integrity monitoring on the WordPress installation directory to detect unauthorized file changes
Correlate HTTP request anomalies with subsequent child process creation under the web server account

Monitoring Recommendations

Forward web server, PHP-FPM, and WordPress audit logs to a centralized SIEM for correlation
Alert on web server users spawning unexpected child processes such as sh, python, perl, or curl
Track newly created administrator users and plugin or theme installations in WordPress

How to Mitigate CVE-2026-48836

Immediate Actions Required

Identify all WordPress installations running the Easy Invoice plugin and confirm the installed version
Deactivate and remove the Easy Invoice plugin on any site running version 2.1.19 or earlier until a fixed version is verified
Rotate WordPress administrator credentials, database passwords, and API keys stored in wp-config.php if compromise is suspected
Review web server logs for evidence of exploitation predating remediation

Patch Information

Consult the Patchstack RCE Vulnerability Report for current vendor fix availability. Upgrade to a plugin release later than 2.1.19 once published by the maintainer. If no patched version is available, removing the plugin is the only complete mitigation.

Workarounds

Block access to Easy Invoice plugin endpoints at the web application firewall (WAF) layer until a patch is applied
Restrict the web server user's filesystem write permissions to limit webshell deployment
Disable dangerous PHP functions such as exec, system, passthru, and shell_exec in php.ini where application compatibility allows

bash

# Configuration example
# Disable Easy Invoice plugin via WP-CLI until a fix is available
wp plugin deactivate easy-invoice
wp plugin delete easy-invoice

# Restrict dangerous PHP functions in php.ini
# disable_functions = exec,passthru,shell_exec,system,proc_open,popen