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.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | roundcube | 1.2.3+dfsg.1-1 | — |
| Debian 13 | roundcube | 1.2.3+dfsg.1-1 | — |
| Debian 12 | roundcube | 1.2.3+dfsg.1-1 | — |
| Debian 7 | roundcube | 0.7.2-9+deb7u5 | DLA-737-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 16.04 LTS | roundcube | 1.2~beta+dfsg.1-0ubuntu1+esm7 | — |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
GitHub 1 repository
-
t0kx/exploit-CVE-2016-9920 ★ 48 · Jan 6, 2017
Roundcube 1.0.0 <= 1.2.2 Remote Code Execution exploit and vulnerable container
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 1
- DLA-737-1 roundcube - security update Debian Security (DSA / DLA) · Mar 9, 2026