CVE-2016-9920

HIGH

Roundcube Webmail < 1.1.7 and 1.2.x < 1.2.3 - Authenticated Remote Code Execution via Sendmail Envelope-From Address

Title source: llm

Exploitation Summary

EIP tracks 1 public exploit for CVE-2016-9920. PoCs published by t0kx.

AI-analyzed exploit summary This repository contains a functional exploit for CVE-2016-9920, a remote code execution vulnerability in Roundcube Webmail versions 1.0.0 to 1.2.2. The exploit leverages unsanitized input in the `mail()` function's fifth argument to execute arbitrary commands via sendmail's `-X` option.

Description

steps/mail/sendmail.inc in Roundcube before 1.1.7 and 1.2.x before 1.2.3, when no SMTP server is configured and the sendmail program is enabled, does not properly restrict the use of custom envelope-from addresses on the sendmail command line, which allows remote authenticated users to execute arbitrary code via a modified HTTP request that sends a crafted e-mail message.

Exploits (1)

nomisec WORKING POC 48 stars

by t0kx · poc

https://github.com/t0kx/exploit-CVE-2016-9920

View Code ZIP pw:eip

This repository contains a functional exploit for CVE-2016-9920, a remote code execution vulnerability in Roundcube Webmail versions 1.0.0 to 1.2.2. The exploit leverages unsanitized input in the `mail()` function's fifth argument to execute arbitrary commands via sendmail's `-X` option.

Classification

Working Poc 95%

Attack Type

Rce

Complexity

Moderate

Reliability

Reliable

Target: Roundcube Webmail 1.0.0 to 1.2.2

Auth required

Prerequisites: Roundcube configured to use PHP's `mail()` function · PHP's `mail()` function configured to use sendmail · PHP `safe_mode` turned off · Knowledge of the absolute path of the webroot

MITRE ATT&CK

T1189 - Drive-by Compromise T1203 - Exploitation for Client Execution

devstral-2 · analyzed Feb 18, 2026 Full analysis →